Quetiapine Fumarate Tablets
TABLE OF CONTENTS
Quetiapine fumarate is a psychotropic agent belonging to a chemical class, the dibenzothiazepine derivatives.
The chemical designation is 2-[2-(4-dibenzo [b,f] [1,4]thiazepin-11-yl-1-piperazinyl)ethoxy]-ethanol fumarate (2:1) (salt). It is present in tablets as the fumarate salt. All doses and tablet strengths are expressed as milligrams of base, not as fumarate salt.
Its molecular formula is C42H50N6O4S2•C4H4O4 and it has a molecular weight of 883.11 (fumarate salt). The structural formula is:
Quetiapine fumarate is a white to off-white crystalline powder which is moderately soluble in water.
Quetiapine is supplied for oral administration as 25 mg (round, peach), 50 mg (round, white), 100 mg (round, yellow), 200 mg (round, white), 300 mg (capsule-shaped, white), and 400 mg (capsule-shaped, yellow) tablets.
Inactive ingredients are povidone, dibasic dicalcium phosphate dihydrate, microcrystalline cellulose, sodium starch glycolate, lactose monohydrate, magnesium stearate, hypromellose, polyethylene glycol and titanium dioxide.
The 25 mg tablets contain red ferric oxide and yellow ferric oxide and the 100 mg and 400 mg tablets contain only yellow ferric oxide.
|2. INDICATIONS AND USAGE|
Quetiapine is indicated for the treatment of schizophrenia. The efficacy of quetiapine in schizophrenia was established in three 6-week trials in adults and one 6-week trial in adolescents (13-17 years). The effectiveness of quetiapine for the maintenance treatment of schizophrenia has not been systematically evaluated in controlled clinical trials.
2.2 Bipolar Disorder
Quetiapine is indicated for the acute treatment of manic episodes associated with bipolar I disorder, both as monotherapy and as an adjunct to lithium or divalproex. Efficacy was established in two 12-week monotherapy trials in adults, in one 3-week adjunctive trial in adults, and in one 3-week monotherapy trial in pediatric patients (10-17 years).
Quetiapine is indicated as monotherapy for the acute treatment of depressive episodes associated with bipolar disorder. Efficacy was established in two 8-week monotherapy trials in adult patients with bipolar I and bipolar II disorder.
Quetiapine is indicated for the maintenance treatment of bipolar I disorder, as an adjunct to lithium or divalproex. Efficacy was established in two maintenance trials in adults. The effectiveness of quetiapine as monotherapy for the maintenance treatment of bipolar disorder has not been systematically evaluated in controlled clinical trials.
2.3 Special Considerations in Treating Pediatric Schizophrenia and Bipolar I Disorder
]Pediatric schizophrenia and bipolar I disorder are serious mental disorders, however, diagnosis can be challenging. For pediatric schizophrenia, symptom profiles can be variable, and for bipolar I disorder, patients may have variable patterns of periodicity of manic or mixed symptoms. It is recommended that medication therapy for pediatric schizophrenia and bipolar I disorder be initiated only after a thorough diagnostic evaluation has been performed and careful consideration given to the risks associated with medication treatment. Medication treatment for both pediatric schizophrenia and bipolar I disorder is indicated as part of a total treatment program that often includes psychological, educational and social interventions.
|3. DOSAGE AND ADMINISTRATION|
Quetiapine can be taken with or without food.
Dose Selection — Quetiapine should generally be administered with an initial dose of 25 mg twice daily, with increases in total daily dose of 25 mg - 50 mg divided in two or three doses on the second and third day, as tolerated, to a total dose range of 300 mg to 400 mg daily by the fourth day. Further dosage adjustments, if indicated, should generally occur at intervals of not less than 2 days, as steady-state for quetiapine would not be achieved for approximately 1-2 days in the typical patient. When dosage adjustments are necessary, dose increments/decrements of 25 mg - 50 mg divided twice daily are recommended. Most efficacy data with quetiapine were obtained using three times daily dosing regimens, but in one controlled trial 225 mg given twice per day was also effective.
Efficacy in schizophrenia was demonstrated in a dose range of 150 mg/day to 750 mg/day in the clinical trials supporting the effectiveness of quetiapine. In a dose response study, doses above 300 mg/day were not demonstrated to be more efficacious than the 300 mg/day dose. In other studies, however, doses in the range of 400 mg/day - 500 mg/day appeared to be needed. The safety of doses above 800 mg/day has not been evaluated in clinical trials.
Maintenance Treatment — The effectiveness of quetiapine for longer than 6 weeks has not been evaluated in controlled clinical trials. While there is no body of evidence available to answer the question of how long the patient treated with quetiapine should be maintained, it is generally recommended that responding patients be continued beyond the acute response, but at the lowest dose needed to maintain remission. Patients should be periodically reassessed to determine the need for maintenance treatment.
Adolescents (13-17 years)
Dose Selection — Quetiapine should be administered twice daily. However, based on response and tolerability quetiapine may be administered three times daily where needed.
The total daily dose for the initial five days of therapy is 50 mg (Day 1), 100 mg (Day 2), 200 mg (Day 3), 300 mg (Day 4) and 400 mg (Day 5). After Day 5, the dose should be adjusted within the recommended dose range of 400 mg/day to 800 mg/day based on response and tolerability. Dosage adjustments should be in increments of no greater than 100 mg/day. Efficacy was demonstrated with quetiapine at both 400 mg and 800 mg; however, no additional benefit was seen in the 800 mg group.
Maintenance Treatment— The effectiveness of quetiapine for longer than 6 weeks has not been evaluated in controlled clinical trials. While there is no body of evidence available to answer the question of how long the patient treated with quetiapine should be maintained, it is generally recommended that responding patients be continued beyond the acute response, but at the lowest dose needed to maintain remission. Patients should be periodically reassessed to determine the need for maintenance treatment.
3.2 Bipolar Disorder
Acute Treatment of Manic Episodes in Bipolar I Disorder
Dose Selection - When used as monotherapy or adjunct therapy (with lithium or divalproex), quetiapine should be initiated in twice daily doses totaling 100 mg/day on Day 1, increased to 400 mg/day on Day 4 in increments of up to 100 mg/day in twice daily divided doses. Further dosage adjustments up to 800 mg/day by Day 6 should be in increments of no greater than 200 mg/day. Data indicate that the majority of patients responded between 400 mg/day to 800 mg/day. The safety of doses above 800 mg/day has not been evaluated in clinical trials.
Acute Treatment of Depressive Episodes in Bipolar Disorder
Dose Selection - Quetiapine should be administered once daily at bedtime to reach 300 mg/day by Day 4.
Table 1. Recommended Dosing Schedule
In the clinical trials supporting effectiveness, the dosing schedule was 50 mg, 100 mg, 200 mg and 300 mg/day for Days 1-4 respectively. Patients receiving 600 mg increased to 400 mg on Day 5 and 600 mg on Day 8 (Week 1). Antidepressant efficacy was demonstrated with quetiapine at both 300 mg and 600 mg; however, no additional benefit was seen in the 600 mg group.
Maintenance Treatment of Bipolar I Disorder
Maintenance of efficacy in bipolar I disorder was demonstrated with quetiapine (administered twice daily totaling 400 to 800 mg per day) as adjunct therapy to lithium or divalproex. Generally, in the maintenance phase, patients continued on the same dose on which they were stabilized during the stabilization phase.
Children and Adolescents (10 to 17 years)
Acute Treatment of Manic Episodes in Bipolar I Disorder
Dose Selection - Quetiapine should be administered twice daily. However, based on response and tolerability quetiapine may be administered three times daily where needed.
The total daily dose for the initial five days of therapy is 50 mg (Day 1), 100 mg (Day 2), 200 mg (Day 3), 300 mg (Day 4) and 400 mg (Day 5). After Day 5, the dose should be adjusted within the recommended dose range of 400 to 600 mg/day based on response and tolerability. Dosage adjustments should be in increments of no greater than 100 mg/day. Efficacy was demonstrated with quetiapine at both 400 mg and 600 mg; however, no additional benefit was seen in the 600 mg group.
Maintenance Treatment of Bipolar I Disorder
The effectiveness of quetiapine for longer than 3 weeks has not been evaluated in controlled clinical trials of children and adolescents. While there is no body of evidence available to answer the question of how long the patient treated with quetiapine should be maintained, it is generally recommended that responding patients be continued beyond the acute response, but at the lowest dose needed to maintain remission. Patients should be periodically reassessed to determine the need for maintenance treatment.
3.3 Dosing in Special Populations
Consideration should be given to a slower rate of dose titration and a lower target dose in the elderly and in patients who are debilitated or who have a predisposition to hypotensive reactions. When indicated, dose escalation should be performed with caution in these patients.
Patients with hepatic impairment should be started on 25 mg/day. The dose should be increased daily in increments of 25 mg/day - 50 mg/day to an effective dose, depending on the clinical response and tolerability of the patient.
3.4 Reinitiation of Treatment in Patients Previously Discontinued
Although there are no data to specifically address reinitiation of treatment, it is recommended that when restarting patients who have had an interval of less than one week off quetiapine, titration of quetiapine is not required and the maintenance dose may be reinitiated. When restarting therapy of patients who have been off quetiapine for more than one week, the initial titration schedule should be followed.
3.5 Switching from Antipsychotics
There are no systematically collected data to specifically address switching patients with schizophrenia from antipsychotics to quetiapine, or concerning concomitant administration with antipsychotics. While immediate discontinuation of the previous antipsychotic treatment may be acceptable for some patients with schizophrenia, more gradual discontinuation may be most appropriate for others. In all cases, the period of overlapping antipsychotic administration should be minimized. When switching patients with schizophrenia from depot antipsychotics, if medically appropriate, initiate quetiapine therapy in place of the next scheduled injection. The need for continuing existing EPS medication should be re-evaluated periodically.
This drug is contraindicated in those patients who are hypersensitive to this drug or any of its components.
|5. MECHANISM OF ACTION|
The mechanism of action of quetiapine, as with other drugs having efficacy in the treatment of schizophrenia and bipolar disorder, is unknown. However, it has been proposed that the efficacy of quetiapine in schizophrenia and its mood stabilizing properties in bipolar depression and mania are mediated through a combination of dopamine type 2 (D2) and serotonin type 2 (5HT2) antagonism. Antagonism at receptors other than dopamine and 5HT2 with similar receptor affinities may explain some of the other effects of quetiapine. Quetiapine’s antagonism of histamine H1 receptors may explain the somnolence observed with this drug.
|6. USE IN SPECIFIC POPULATIONS|
6.1 Usage in Pregnancy
Pregnancy Category C
There are no adequate and well-controlled studies in pregnant women, this drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Neonates exposed to antipsychotic drugs (including quetiapine), during the third trimester of pregnancy are at risk for extrapyramidal and/or withdrawal symptoms following delivery. There have been reports of agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress and feeding disorder in these neonates. These complications have varied in severity; while in some cases symptoms have been self-limited, in other cases neonates have required intensive care unit support and prolonged hospitalization.
6.2 Labor and Delivery
The effect of quetiapine on labor and delivery in humans is unknown.
6.3 Nursing Mothers
Quetiapine was excreted into human milk. It is recommended that women receiving quetiapine should not breast feed.
In published case reports, the level of quetiapine in breast milk ranged from undetectable to 170 μg/L. The estimated infant dose ranged from 0.09% to 0.43% of the weight-adjusted maternal dose. Based on a limited number (N=8) of mother/infant pairs, calculated infant daily doses range from less than 0.01 mg/kg (at a maternal daily dose up to 100 mg quetiapine) to 0.1 mg/kg (at a maternal daily dose of 400 mg).
6.4 Pediatric Use
In general, the adverse reactions observed in children and adolescents during the clinical trials were similar to those in the adult population with few exceptions. Increases in systolic and diastolic blood pressure occurred in children and adolescents and did not occur in adults. Orthostatic hypotension occurred more frequently in adults (4-7%) compared to children and adolescents (< 1%).
The efficacy and safety of quetiapine in the treatment of schizophrenia in adolescents aged 13 to 17 years were demonstrated in one 6-week, double-blind, placebo-controlled trial [see Indications and Usage, Dosage and Administration, Adverse Reactions].
Safety and effectiveness of quetiapine in pediatric patients less than 13 years of age with schizophrenia have not been established.
The safety and effectiveness of quetiapine in the maintenance treatment of bipolar disorder has not been established in pediatric patients less than 18 years of age. The safety and effectiveness of quetiapine in the maintenance treatment of schizophrenia has not been established in any patient population, including pediatric patients.
The efficacy and safety of quetiapine in the treatment of mania in children and adolescents ages 10 to 17 years with Bipolar I disorder was demonstrated in a 3-week, double-blind, placebo controlled, multicenter trial [see Indications and Usage, Dosage and Administration, Adverse Reactions].
Safety and effectiveness of quetiapine in pediatric patients less than 10 years of age with bipolar mania have not been established.
Safety and effectiveness of quetiapine in pediatric patients less than 18 years of age with bipolar depression have not been established.
Some differences in the pharmacokinetics of quetiapine were noted between children/adolescents (10 to 17 years of age) and adults. When adjusted for weight, the AUC and Cmax of quetiapine were 41% and 39% lower, respectively, in children and adolescents compared to adults. The pharmacokinetics of the active metabolite, norquetiapine, were similar between children/adolescents and adults after adjusting for weight.
6.5 Geriatric Use
Of the approximately 3700 patients in clinical studies with quetiapine, 7% (232) were 65 years of age or over. In general, there was no indication of any different tolerability of quetiapine in the elderly compared to younger adults. Nevertheless, the presence of factors that might decrease pharmacokinetic clearance, increase the pharmacodynamic response to quetiapine, or cause poorer tolerance or orthostasis, should lead to consideration of a lower starting dose, slower titration, and careful monitoring during the initial dosing period in the elderly. The mean plasma clearance of quetiapine was reduced by 30% to 50% in elderly patients when compared to younger patients [see Dosage and Administration].
|7. WARNINGS AND PRECAUTIONS|
7.1 Increased Mortality in Elderly Patients with Dementia-Related Psychosis
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Quetiapine fumarate is not approved for the treatment of patients with dementia-related psychosis (see Boxed Warning).
7.2 Clinical Worsening and Suicide Risk
Patients with major depressive disorder (MDD), both adult and pediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders, and these disorders themselves are the strongest predictors of suicide. There has been a long-standing concern, however, that antidepressants may have a role in inducing worsening of depression and the emergence of suicidality in certain patients during the early phases of treatment. Pooled analyses of short-term placebo-controlled trials of antidepressant drugs (SSRIs and others) showed that these drugs increase the risk of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults (ages 18-24) with major depressive disorder (MDD) and other psychiatric disorders. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction with antidepressants compared to placebo in adults aged 65 and older.
No suicides occurred in any of the pediatric trials. There were suicides in the adult trials, but the number was not sufficient to reach any conclusion about drug effect on suicide.
It is unknown whether the suicidality risk extends to longer-term use, i.e., beyond several months. However, there is substantial evidence from placebo-controlled maintenance trials in adults with depression that the use of antidepressants can delay the recurrence of depression.
All patients being treated with antidepressants for any indication should be monitored appropriately and observed closely for clinical worsening, suicidality, and unusual changes in behavior, especially during the initial few months of a course of drug therapy, or at times of dose changes, either increases or decreases.
The following symptoms, anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, and mania, have been reported in adult and pediatric patients being treated with antidepressants for major depressive disorder as well as for other indications, both psychiatric and nonpsychiatric. Although a causal link between the emergence of such symptoms and either the worsening of depression and/or the emergence of suicidal impulses has not been established, there is concern that such symptoms may represent precursors to emerging suicidality.
Consideration should be given to changing the therapeutic regimen, including possibly discontinuing the medication, in patients whose depression is persistently worse, or who are experiencing emergent suicidality or symptoms that might be precursors to worsening depression or suicidality, especially if these symptoms are severe, abrupt in onset, or were not part of the patient’s presenting symptoms.
Families and caregivers of patients being treated with antidepressants for major depressive disorder or other indications, both psychiatric and nonpsychiatric, should be alerted about the need to monitor patients for the emergence of agitation, irritability, unusual changes in behavior, and the other symptoms described above, as well as the emergence of suicidality, and to report such symptoms immediately to healthcare providers. Such monitoring should include daily observation by families and caregivers. Prescriptions for quetiapine should be written for the smallest quantity of tablets consistent with good patient management, in order to reduce the risk of overdose.
Screening Patients for Bipolar Disorder: A major depressive episode may be the initial presentation of bipolar disorder. It is generally believed (though not established in controlled trials) that treating such an episode with an antidepressant alone may increase the likelihood of precipitation of a mixed/manic episode in patients at risk for bipolar disorder. Whether any of the symptoms described above represent such a conversion is unknown. However, prior to initiating treatment with an antidepressant, patients with depressive symptoms should be adequately screened to determine if they are at risk for bipolar disorder; such screening should include a detailed psychiatric history, including a family history of suicide, bipolar disorder, and depression. It should be noted that quetiapine is approved for use in treating adult bipolar depression.
7.3 Neuroleptic Malignant Syndrome (NMS)
A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with administration of antipsychotic drugs, including quetiapine. Rare cases of NMS have been reported with quetiapine. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status, and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis, and cardiac dysrhythmia). Additional signs may include elevated creatine phosphokinase, myoglobinuria (rhabdomyolysis) and acute renal failure.
The diagnostic evaluation of patients with this syndrome is complicated. In arriving at a diagnosis, it is important to exclude cases where the clinical presentation includes both serious medical illness (e.g., pneumonia, systemic infection, etc.) and untreated or inadequately treated extrapyramidal signs and symptoms (EPS). Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever and primary central nervous system (CNS) pathology.
The management of NMS should include: 1) immediate discontinuation of antipsychotic drugs and other drugs not essential to concurrent therapy; 2) intensive symptomatic treatment and medical monitoring; and 3) treatment of any concomitant serious medical problems for which specific treatments are available. There is no general agreement about specific pharmacological treatment regimens for NMS.
If a patient requires antipsychotic drug treatment after recovery from NMS, the potential reintroduction of drug therapy should be carefully considered. The patient should be carefully monitored since recurrences of NMS have been reported.
7.4 Hyperglycemia and Diabetes Mellitus
Hyperglycemia, in some cases extreme and associated with ketoacidosis or hyperosmolar coma or death, has been reported in patients treated with atypical antipsychotics, including quetiapine. Assessment of the relationship between atypical antipsychotic use and glucose abnormalities is complicated by the possibility of an increased background risk of diabetes mellitus in patients with schizophrenia and the increasing incidence of diabetes mellitus in the general population. Given these confounders, the relationship between atypical antipsychotic use and hyperglycemiarelated adverse reactions is not completely understood. However, epidemiological studies suggest an increased risk of treatment-emergent hyperglycemia-related adverse reactions in patients treated with the atypical antipsychotics. Precise risk estimates for hyperglycemia-related adverse reactions in patients treated with atypical antipsychotics are not available.
Patients with an established diagnosis of diabetes mellitus who are started on atypical antipsychotics should be monitored regularly for worsening of glucose control. Patients with risk factors for diabetes mellitus (eg, obesity, family history of diabetes) who are starting treatment with atypical antipsychotics should undergo fasting blood glucose testing at the beginning of treatment and periodically during treatment. Any patient treated with atypical antipsychotics should be monitored for symptoms of hyperglycemia including polydipsia, polyuria, polyphagia, and weakness. Patients who develop symptoms of hyperglycemia during treatment with atypical antipsychotics should undergo fasting blood glucose testing. In some cases, hyperglycemia has resolved when the atypical antipsychotic was discontinued; however, some patients required continuation of anti-diabetic treatment despite discontinuation of the suspect drug.
In some patients, a worsening of more than one of the metabolic parameters of weight, blood glucose and lipids was observed in clinical studies. Changes in these parameters should be managed as clinically appropriate.
Undesirable alterations in lipids have been observed with quetiapine use. Clinical monitoring, including baseline and periodic follow-up lipid evaluations in patients using quetiapine is recommended.
In some patients, a worsening of more than one of the metabolic parameters of weight, blood glucose and lipids was observed in clinical studies. Changes in these parameters should be managed as clinically appropriate.
Adults: In clinical trials with quetiapine the percentage of patients with the following changes in cholesterol and triglycerides have been reported [see Adverse Reactions].
Table 2. Percentage of Patients with Shifts from Normal Baseline to Clinically Significant Levels
7.6 Weight Gain
Increases in weight have been observed in clinical trials. Patients receiving quetiapine should receive regular monitoring of weight.
In some patients, a worsening of more than one of the metabolic parameters of weight, blood glucose and lipids was observed in clinical studies. Changes in these parameters should be managed as clinically appropriate.
Adults: In clinical trials with quetiapine the following increases in weight have been reported.
Table 3. Proportion of Patients with Weight Gain ≥7% of Body Weight (Adults)
7.7 Tardive Dyskinesia
A syndrome of potentially irreversible, involuntary, dyskinetic movements may develop in patients treated with antipsychotic drugs, including quetiapine. Although the prevalence of the syndrome appears to be highest among the elderly, especially elderly women, it is impossible to rely upon prevalence estimates to predict, at the inception of antipsychotic treatment, which patients are likely to develop the syndrome. Whether antipsychotic drug products differ in their potential to cause tardive dyskinesia is unknown.
The risk of developing tardive dyskinesia and the likelihood that it will become irreversible are believed to increase as the duration of treatment and the total cumulative dose of antipsychotic drugs administered to the patient increase. However, the syndrome can develop, although much less commonly, after relatively brief treatment periods at low doses or may even arise after discontinuation of treatment.
There is no known treatment for established cases of tardive dyskinesia, although the syndrome may remit, partially or completely, if antipsychotic treatment is withdrawn. Antipsychotic treatment, itself, however, may suppress (or partially suppress) the signs and symptoms of the syndrome and thereby may possibly mask the underlying process. The effect that symptomatic suppression has upon the long-term course of the syndrome is unknown.
Given these considerations, quetiapine should be prescribed in a manner that is most likely to minimize the occurrence of tardive dyskinesia. Chronic antipsychotic treatment should generally be reserved for patients who appear to suffer from a chronic illness that (1) is known to respond to antipsychotic drugs, and (2) for whom alternative, equally effective, but potentially less harmful treatments are not available or appropriate. In patients who do require chronic treatment, the smallest dose and the shortest duration of treatment producing a satisfactory clinical response should be sought. The need for continued treatment should be reassessed periodically.
If signs and symptoms of tardive dyskinesia appear in a patient on quetiapine, drug discontinuation should be considered. However, some patients may require treatment with quetiapine despite the presence of the syndrome.
7.8 Orthostatic Hypotension
Quetiapine may induce orthostatic hypotension associated with dizziness, tachycardia and, in some patients, syncope, especially during the initial dose-titration period, probably reflecting its α1-adrenergic antagonist properties. Syncope was reported in 1% (28/3265) of the patients treated with quetiapine, compared with 0.2% (2/954) on placebo and about 0.4% (2/527) on active control drugs. Orthostatic hypotension, dizziness, and syncope may lead to falls.
Quetiapine should be used with particular caution in patients with known cardiovascular disease (history of myocardial infarction or ischemic heart disease, heart failure or conduction abnormalities), cerebrovascular disease or conditions which would predispose patients to hypotension (dehydration, hypovolemia and treatment with antihypertensive medications). The risk of orthostatic hypotension and syncope may be minimized by limiting the initial dose to 25 mg twice daily [see Dosage and Administration]. If hypotension occurs during titration to the target dose, a return to the previous dose in the titration schedule is appropriate.
7.9 Increases in Blood Pressure in Children and Adolescents
In placebo-controlled trials in children and adolescents with schizophrenia (6-week duration) or bipolar mania (3-week duration), the incidence of increases at any time in systolic blood pressure (≥20 mmHg) was 15.2% (51/335) for quetiapine and 5.5% (9/163) for placebo; the incidence of increases at any time in diastolic blood pressure (≥10 mmHg) was 40.6% (136/335) for quetiapine and 24.5% (40/163) for placebo. In the 26-week open-label clinical trial, one child with a reported history of hypertension experienced a hypertensive crisis. Blood pressure in children and adolescents should be measured at the beginning of, and periodically during treatment.
7.10 Leukopenia, Neutropenia and Agranulocytosis
In clinical trials and postmarketing experience, events of leukopenia/neutropenia have been reported temporally related to atypical antipsychotic agents, including quetiapine. Agranulocytosis (including fatal cases) has also been reported.
Possible risk factors for leukopenia/neutropenia include pre-existing low white cell count (WBC) and history of drug induced leukopenia/neutropenia. Patients with a pre-existing low WBC or a history of drug induced leukopenia/neutropenia should have their complete blood count (CBC) monitored frequently during the first few months of therapy and should discontinue quetiapine at the first sign of a decline in WBC in absence of other causative factors.
Patients with neutropenia should be carefully monitored for fever or other symptoms or signs of infection and treated promptly if such symptoms or signs occur. Patients with severe neutropenia (absolute neutrophil count <1000/mm3) should discontinue quetiapine and have their WBC followed until recovery [see Adverse Reactions].
The development of cataracts was observed in association with quetiapine treatment in chronic dog studies. Lens changes have also been observed in patients during long-term quetiapine treatment, but a causal relationship to quetiapine use has not been established. Nevertheless, the possibility of lenticular changes cannot be excluded at this time. Therefore, examination of the lens by methods adequate to detect cataract formation, such as slit lamp exam or other appropriately sensitive methods, is recommended at initiation of treatment or shortly thereafter, and at 6-month intervals during chronic treatment.
7.12 QT Prolongation
In clinical trials quetiapine was not associated with a persistent increase in QT intervals. However, the QT effect was not systematically evaluated in a thorough QT study. In post marketing experience, there were cases reported of QT prolongation in patients who overdosed on quetiapine [see Overdosage], in patients with concomitant illness, and in patients taking medicines known to cause electrolyte imbalance or increase QT interval [see Drug Interactions].
The use of quetiapine should be avoided in combination with other drugs that are known to prolong QTc including Class 1A antiarrythmics (e.g., quinidine, procainamide) or Class III antiarrythmics (e.g., amiodarone, sotalol), antipsychotic medications (e.g., ziprasidone, chlorpromazine, thioridazine), antibiotics (e.g., gatifloxacin, moxifloxacin), or any other class of medications known to prolong the QTc interval (e.g., pentamidine, levomethadyl acetate, methadone).
Quetiapine should also be avoided in circumstances that may increase the risk of occurrence of torsade de pointes and/or sudden death including (1) a history of cardiac arrhythmias such as bradycardia; (2) hypokalemia or hypomagnesemia; (3) concomitant use of other drugs that prolong the QTc interval; and (4) presence of congenital prolongation of the QT interval.
Caution should also be exercised when quetiapine is prescribed in patients with increased risk of QT prolongation (e.g. cardiovascular disease, family history of QT prolongation, the elderly, congestive heart failure and heart hypertrophy).
During clinical trials, seizures occurred in 0.5% (20/3490) of patients treated with quetiapine compared to 0.2% (2/954) on placebo and 0.7% (4/527) on active control drugs. As with other antipsychotics, quetiapine should be used cautiously in patients with a history of seizures or with conditions that potentially lower the seizure threshold, eg, Alzheimer’s dementia. Conditions that lower the seizure threshold may be more prevalent in a population of 65 years or older.
Adults: Clinical trials with quetiapine demonstrated a dose-related decrease in total and free thyroxine (T4) of approximately 20% at the higher end of the therapeutic dose range and was maximal in the first two to four weeks of treatment and maintained without adaptation or progression during more chronic therapy. Generally, these changes were of no clinical significance and TSH was unchanged in most patients and levels of TBG were unchanged. In nearly all cases, cessation of quetiapine treatment was associated with a reversal of the effects on total and free T4, irrespective of the duration of treatment. About 0.7% (26/3489) of quetiapine patients did experience TSH increases in monotherapy studies. Six of the patients with TSH increases needed replacement thyroid treatment. In the mania adjunct studies, where quetiapine was added to lithium or divalproex, 12% (24/196) of quetiapine treated patients compared to 7% (15/203) of placebo-treated patients had elevated TSH levels. Of the quetiapine treated patients with elevated TSH levels, 3 had simultaneous low free T4 levels.
Adults: During clinical trials with quetiapine, the incidence of shifts in prolactin levels to a clinically significant value occurred in 3.6% (158/4416) of patients treated with quetiapine compared to 2.6% (51/1968) on placebo.
Like other drugs that antagonize dopamine D2 receptors, quetiapine elevates prolactin levels in some patients and the elevation may persist during chronic administration. Hyperprolactinemia, regardless of etiology, may suppress hypothalamic GnRH, resulting in reduced pituitary gonadotrophin secretion. This, in turn, may inhibit reproductive function by impairing gonadal steroidogenesis in both female and male patients. Galactorrhea, amenorrhea, gynecomastia, and impotence have been reported in patients receiving prolactin-elevating compounds. Long-standing hyperprolactinemia when associated with hypogonadism may lead to decreased bone density in both female and male subjects.
7.16 Transaminase Elevations
Asymptomatic, transient and reversible elevations in serum transaminases (primarily ALT) have been reported. In schizophrenia trials, the proportions of patients with transaminase elevations of >3 times the upper limits of the normal reference range in a pool of 3- to 6-week placebo-controlled trials were approximately 6% for quetiapine compared to 1% for placebo. In acute bipolar mania trials, the proportions of patients with transaminase elevations of >3 times the upper limits of the normal reference range in a pool of 3- to 12-week placebo-controlled trials were approximately 1% for both quetiapine and placebo. These hepatic enzyme elevations usually occurred within the first 3 weeks of drug treatment and promptly returned to pre-study levels with ongoing treatment with quetiapine. In bipolar depression trials, the proportions of patients with transaminase elevations of >3 times the upper limits of the normal reference range in two 8-week placebo-controlled trials was 1% for quetiapine and 2% for placebo.
7.17 Potential for Cognitive and Motor Impairment
Somnolence was a commonly reported adverse event reported in patients treated with quetiapine especially during the 3-5 day period of initial dose-titration. In schizophrenia trials, somnolence was reported in 18% of patients on quetiapine compared to 11% of placebo patients. In acute bipolar mania trials using quetiapine as monotherapy, somnolence was reported in 16% of patients on quetiapine compared to 4% of placebo patients. In acute bipolar mania trials using quetiapine as adjunct therapy, somnolence was reported in 34% of patients on quetiapine compared to 9% of placebo patients. In bipolar depression trials, somnolence was reported in 57% of patients on quetiapine compared to 15% of placebo patients. Since quetiapine has the potential to impair judgment, thinking, or motor skills, patients should be cautioned about performing activities requiring mental alertness, such as operating a motor vehicle (including automobiles) or operating hazardous machinery until they are reasonably certain that quetiapine therapy does not affect them adversely. Somnolence may lead to falls.
One case of priapism in a patient receiving quetiapine has been reported prior to market introduction. While a causal relationship to use of quetiapine has not been established, other drugs with alpha-adrenergic blocking effects have been reported to induce priapism, and it is possible that quetiapine may share this capacity. Severe priapism may require surgical intervention.
7.19 Body Temperature Regulation
Although not reported with quetiapine, disruption of the body’s ability to reduce core body temperature has been attributed to antipsychotic agents. Appropriate care is advised when prescribing quetiapine for patients who will be experiencing conditions which may contribute to an elevation in core body temperature, e.g., exercising strenuously, exposure to extreme heat, receiving concomitant medication with anticholinergic activity, or being subject to dehydration.
Esophageal dysmotility and aspiration have been associated with antipsychotic drug use. Aspiration pneumonia is a common cause of morbidity and mortality in elderly patients, in particular those with advanced Alzheimer’s dementia. Quetiapine and other antipsychotic drugs should be used cautiously in patients at risk for aspiration pneumonia.
The possibility of a suicide attempt is inherent in bipolar disorder and schizophrenia; close supervision of high risk patients should accompany drug therapy. Prescriptions for quetiapine should be written for the smallest quantity of tablets consistent with good patient management in order to reduce the risk of overdose.
7.22 Use in Patients with Concomitant Illness
Clinical experience with quetiapine in patients with certain concomitant systemic illnesses is limited.
Quetiapine has not been evaluated or used to any appreciable extent in patients with a recent history of myocardial infarction or unstable heart disease. Patients with these diagnoses were excluded from premarketing clinical studies. Because of the risk of orthostatic hypotension with quetiapine, caution should be observed in cardiac patients.
Acute withdrawal symptoms, such as nausea, vomiting, and insomnia have very rarely been described after abrupt cessation of atypical antipsychotic drugs, including quetiapine. In short-term placebo-controlled, monotherapy clinical trials with quetiapine ER that included a discontinuation phase which evaluated discontinuation symptoms, the aggregated incidence of patients experiencing one or more discontinuation symptoms after abrupt cessation was 12.1% (241/1993) for quetiapine ER and 6.7% (71/1065) for placebo. The incidence of the individual adverse events (i.e., insomnia, nausea, headache, diarrhea, vomiting, dizziness and irritability) did not exceed 5.3% in any treatment group and usually resolved after 1 week post-discontinuation. Gradual withdrawal is advised.
|8. ADVERSE REACTIONS|
8.1 Clinical Study Experience
Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.
The information below is derived from a clinical trial database for quetiapine consisting of over 4300 patients. This database includes 698 patients exposed to quetiapine for the treatment of bipolar depression, 405 patients exposed to quetiapine for the treatment of acute bipolar mania (monotherapy and adjunct therapy), 646 patients exposed to quetiapine for the maintenance treatment of bipolar I disorder as adjunct therapy, and approximately 2600 patients and/or normal subjects exposed to 1 or more doses of quetiapine for the treatment of schizophrenia.
Of these approximately 4300 subjects, approximately 4000 (2300 in schizophrenia, 405 in acute bipolar mania, 698 in bipolar depression, and 646 for the maintenance treatment of bipolar I disorder) were patients who participated in multiple dose effectiveness trials, and their experience corresponded to approximately 2400 patient-years. The conditions and duration of treatment with quetiapine varied greatly and included (in overlapping categories) open-label and double-blind phases of studies, inpatients and outpatients, fixed-dose and dose-titration studies, and short-term or longer-term exposure. Adverse reactions were assessed by collecting adverse events, results of physical examinations, vital signs, weights, laboratory analyses, ECGs, and results of ophthalmologic examinations.
Adverse reactions during exposure were obtained by general inquiry and recorded by clinical investigators using terminology of their own choosing. Consequently, it is not possible to provide a meaningful estimate of the proportion of individuals experiencing adverse reactions without first grouping similar types of reactions into a smaller number of standardized reaction categories.
In the tables and tabulations that follow, standard COSTART terminology has been used to classify reported adverse reactions for schizophrenia and bipolar mania. MedDRA terminology has been used to classify reported adverse reactions for bipolar depression.
The stated frequencies of adverse reactions represent the proportion of individuals who experienced, at least once, a treatment-emergent adverse reaction of the type listed. A reaction was considered treatment emergent if it occurred for the first time or worsened while receiving therapy following baseline evaluation.
Incidence of Adverse Reactions in Short-Term, Placebo-Controlled Trials in Adults
Adverse Reactions Associated with Discontinuation of Treatment in Short-Term, Placebo-Controlled Trials:
Overall, there was little difference in the incidence of discontinuation due to adverse reactions (4% for quetiapine vs. 3% for placebo) in a pool of controlled trials. However, discontinuations due to somnolence (0.8% quetiapine vs. 0% placebo) and hypotension (0.4% quetiapine vs. 0% placebo) were considered to be drug related [see Warnings and Precautions].
Mania: Overall, discontinuations due to adverse reactions were 5.7% for quetiapine vs. 5.1% for placebo in monotherapy and 3.6% for quetiapine vs. 5.9% for placebo in adjunct therapy.
Depression: Overall, discontinuations due to adverse reactions were 12.3% for quetiapine 300 mg vs. 19.0% for quetiapine 600 mg and 5.2% for placebo.
Commonly Observed Adverse Reactions in Short-Term, Placebo-Controlled Trials:
In the acute therapy of schizophrenia (up to 6 weeks) and bipolar mania (up to 12 weeks) trials, the most commonly observed adverse reactions associated with the use of quetiapine monotherapy (incidence of 5% or greater) and observed at a rate on quetiapine at least twice that of placebo were somnolence (18%), dizziness (11%), dry mouth (9%), constipation (8%), ALT increased (5%), weight gain (5%), and dyspepsia (5%).
Adverse Reactions Occurring at an Incidence of 1% or More Among Quetiapine Treated Patients in Short-Term, Placebo-Controlled Trials:
The prescriber should be aware that the figures in the tables and tabulations cannot be used to predict the incidence of side effects in the course of usual medical practice where patient characteristics and other factors differ from those that prevailed in the clinical trials. Similarly, the cited frequencies cannot be compared with figures obtained from other clinical investigations involving different treatments, uses, and investigators. The cited figures, however, do provide the prescribing physician with some basis for estimating the relative contribution of drug and nondrug factors to the side effect incidence in the population studied.
Table 4 enumerates the incidence, rounded to the nearest percent, of treatment-emergent adverse reactions that occurred during acute therapy of schizophrenia (up to 6 weeks) and bipolar mania (up to 12 weeks) in 1% or more of patients treated with quetiapine (doses ranging from 75 to 800 mg/day) where the incidence in patients treated with quetiapine was greater than the incidence in placebo-treated patients.
Table 4. Treatment-Emergent Adverse Reaction Incidence in 3- to 12-Week Placebo-Controlled Clinical Trials for the Treatment of Schizophrenia and Bipolar Mania (Monotherapy)1
1 Reactions for which the quetiapine incidence was equal to or less than placebo are not listed in the table, but included the following: accidental injury, akathisia, chest pain, cough increased, depression, diarrhea, extrapyramidal syndrome, hostility, hypertension, hypertonia, hypotension, increased appetite, infection, insomnia, leukopenia, malaise, nausea, nervousness, paresthesia, peripheral edema, sweating, tremor, and weight loss.
In the acute adjunct therapy of bipolar mania (up to 3 weeks) studies, the most commonly observed adverse reactions associated with the use of quetiapine (incidence of 5% or greater) and observed at a rate on quetiapine at least twice that of placebo were somnolence (34%), dry mouth (19%), asthenia (10%), constipation (10%), abdominal pain (7%), postural hypotension (7%), pharyngitis (6%), and weight gain (6%).
Table 5 enumerates the incidence, rounded to the nearest percent, of treatment-emergent adverse reactions that occurred during therapy (up to 3 weeks) of acute mania in 1% or more of patients treated with quetiapine (doses ranging from 100 to 800 mg/day) used as adjunct therapy to lithium and divalproex where the incidence in patients treated with quetiapine was greater than the incidence in placebo-treated patients.
Table 5. Treatment-Emergent Adverse Reaction Incidence in 3-Week Placebo-Controlled Clinical Trials for the Treatment of Bipolar Mania (Adjunct Therapy)1
1 Reactions for which the quetiapine incidence was equal to or less than placebo are not listed in the table, but included the following: akathisia, diarrhea, insomnia, nausea, accidental injury, chest pain, face edema, flu syndrome, electrocardiogram abnormal, vomiting, gastritis, SGPT increased, weight loss, nervousness, paresthesia, extrapyramidal syndrome, confusion, cough increased, rash and urinary incontinence.
In bipolar depression studies (up to 8 weeks), the most commonly observed treatment emergent adverse reactions associated with the use of quetiapine (incidence of 5% or greater) and observed at a rate on quetiapine at least twice that of placebo were somnolence (57%), dry mouth (44%), dizziness (18%), constipation (10%), and lethargy (5%).
Table 6 enumerates the incidence, rounded to the nearest percent, of treatment-emergent adverse reactions that occurred during therapy (up to 8 weeks) of bipolar depression in 1% or more of patients treated with quetiapine (doses of 300 and 600 mg/day) where the incidence in patients treated with quetiapine was greater than the incidence in placebo-treated patients.
Table 6. Treatment-Emergent Adverse Reaction Incidence in 8Week Placebo-Controlled Clinical Trials for the Treatment of Bipolar Depression1
1 Reactions for which the quetiapine incidence was equal to or less than placebo are not listed in the table, but included the following: nausea, upper respiratory tract infection, headache, tinnitus, diarrhea, flatulence, toothache, stomach discomfort, abdominal pain, pyrexia, peripheral edema, nasopharyngitis, influenza, bronchitis, viral gastroenteritis, accidental overdose, decreased appetite, back pain, muscle twitching, myalgia, muscle cramp, headache, insomnia, anxiety, nightmare, libido decreased, suicidal ideation, pollakiuria, dyspnoea, pharyngolaryngeal pain, night sweats and hot flush.
2 Somnolence combines adverse reaction terms somnolence and sedation.
Explorations for interactions on the basis of gender, age, and race did not reveal any clinically meaningful differences in the adverse reaction occurrence on the basis of these demographic factors.
Dose Dependency of Adverse Reactions in Short-Term, Placebo-Controlled Trials
Dose-related Adverse Reactions: Spontaneously elicited adverse reaction data from a study of schizophrenia comparing five fixed doses of quetiapine (75 mg, 150 mg, 300 mg, 600 mg, and 750 mg/day) to placebo were explored for dose-relatedness of adverse reactions. Logistic regression analyses revealed a positive dose response (p< 0.05) for the following adverse reactions: dyspepsia, abdominal pain, and weight gain.
Adverse Reactions in clinical trials with quetiapine and not listed elsewhere in the label:
The following adverse reactions have also been reported with quetiapine: nightmares, hypersensitivity and elevations in serum creatine phosphokinase (not associated with NMS).
8.2 Vital Signs and Laboratory Values
Hyperglycemia, hyperlipidemia, weight gain, orthostatic hypotension and changes in thyroid hormone levels have been reported with quetiapine. Increases in blood pressure have also been reported with quetiapine in children and adolescents [see Warnings and Precautions].
In placebo-controlled monotherapy clinical trials involving 3368 patients on quetiapine fumarate and 1515 on placebo, the incidence of at least one occurrence of neutrophil count < 1.0 x 109/L among patients with a normal baseline neutrophil count and at least one available follow up laboratory measurement was 0.3% (10/2967) in patients treated with quetiapine fumarate, compared to 0.1% (2/1349) in patients treated with placebo. Patients with a pre-existing low WBC or a history of drug induced leukopenia/neutropenia should have their complete blood count (CBC) monitored frequently during the first few months of therapy and should discontinue quetiapine at the first sign of a decline in WBC in absence of other causative factors [see Warnings and Precautions].
In short-term placebo-controlled trials, decreases in hemoglobin to ≤ 13 g/dL males, ≤ 12 g/dL females on at least one occasion occurred in 8.3% (594/7155) of quetiapine-treated patients compared to 6.2% (219/3536) of patients treated with placebo. In a database of controlled and uncontrolled clinical trials, decreases in hemoglobin to ≤ 13 g/dL males, ≤ 12 g/dL females on at least one occasion occurred in 11% (2277/20729) of quetiapine-treated patients.
Adults: Between-group comparisons for pooled placebo-controlled trials revealed no statistically significant quetiapine/placebo differences in the proportions of patients experiencing potentially important changes in ECG parameters, including QT, QTc, and PR intervals. However, the proportions of patients meeting the criteria for tachycardia were compared in four 3- to 6-week placebo-controlled clinical trials for the treatment of schizophrenia revealing a 1% (4/399) incidence for quetiapine compared to 0.6% (1/156) incidence for placebo. In acute (monotherapy) bipolar mania trials the proportions of patients meeting the criteria for tachycardia was 0.5% (1/192) for quetiapine compared to 0% (0/178) incidence for placebo. In acute bipolar mania (adjunct) trials the proportions of patients meeting the same criteria was 0.6% (1/166) for quetiapine compared to 0% (0/171) incidence for placebo. In bipolar depression trials, no patients had heart rate increases to > 120 beats per minute. Quetiapine use was associated with a mean increase in heart rate, assessed by ECG, of 7 beats per minute compared to a mean increase of 1 beat per minute among placebo patients. This slight tendency to tachycardia in adults may be related to quetiapine's potential for inducing orthostatic changes [see Warnings and Precautions].
Children and Adolescents: In the acute (6 week) schizophrenia trial in adolescents, potentially clinically significant increases in heart rate (> 110 bpm) occurred in 5.2% (3/73) of patients receiving quetiapine 400 mg and 8.5% (5/74) of patients receiving quetiapine 800 mg compared to 0% (0/75) of patients receiving placebo. Mean increases in heart rate were 3.8 bpm and 11.2 bpm for quetiapine 400 mg and 800 mg groups, respectively, compared to a decrease of 3.3 bpm in the placebo group [see Warnings and Precautions].
In the acute (3 week) bipolar mania trial in children and adolescents, potentially clinically significant increases in heart rate (> 110 bpm) occurred in 1.1% (1/95) of patients receiving quetiapine 400 mg and 2.4% (2/98) of patients receiving quetiapine 600 mg compared to 0% (0/98) of patients receiving placebo. Mean increases in heart rate were 12.8 bpm and 13.4 bpm for quetiapine 400 mg and 600 mg groups, respectively, compared to a decrease of 1.7 bpm in the placebo group [see Warnings and Precautions].
8.3 Post Marketing Experience
The following adverse reactions were identified during post approval of quetiapine. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Adverse reactions reported since market introduction which were temporally related to quetiapine therapy include: anaphylactic reaction and galactorrhea.
Other adverse reactions reported since market introduction, which were temporally related to quetiapine therapy, but not necessarily causally related, include the following: agranulocytosis, cardiomyopathy, hyponatremia, myocarditis, rhabdomyolysis, syndrome of inappropriate antidiuretic hormone secretion (SIADH), Stevens-Johnson syndrome (SJS), and decreased platelets.
In post-marketing clinical trials, elevations in total cholesterol (predominantly LDL cholesterol) and somnambulism (and other related events) have been reported.
Human experience: In clinical trials, survival has been reported in acute overdoses of up to 30 grams of quetiapine. Most patients who overdosed experienced no adverse events or recovered fully from the reported events. Death has been reported in a clinical trial following an overdose of 13.6 grams of quetiapine alone. In general, reported signs and symptoms were those resulting from an exaggeration of the drug’s known pharmacological effects, ie, drowsiness and sedation, tachycardia and hypotension. Patients with pre-existing severe cardiovascular disease may be at an increased risk of the effects of overdose.
Management of Overdosage:
In case of acute overdosage, establish and maintain an airway and ensure adequate oxygenation and ventilation. Gastric lavage (after intubation, if patient is unconscious) and administration of activated charcoal together with a laxative should be considered. The possibility of obtundation, seizure or dystonic reaction of the head and neck following overdose may create a risk of aspiration with induced emesis. Cardiovascular monitoring should commence immediately and should include continuous electrocardiographic monitoring to detect possible arrhythmias. If antiarrhythmic therapy is administered, disopyramide, procainamide and quinidine carry a theoretical hazard of additive QT-prolonging effects when administered in patients with acute overdosage of quetiapine. Similarly it is reasonable to expect that the alpha-adrenergic-blocking properties of bretylium might be additive to those of quetiapine, resulting in problematic hypotension.
There is no specific antidote to quetiapine. Therefore appropriate supportive measures should be instituted. The possibility of multiple drug involvement should be considered. Hypotension and circulatory collapse should be treated with appropriate measures such as intravenous fluids and/or sympathomimetic agents (epinephrine and dopamine should not be used, since beta stimulation may worsen hypotension in the setting of quetiapine-induced alpha blockade). In cases of severe extrapyramidal symptoms, anticholinergic medication should be administered. Close medical supervision and monitoring should continue until the patient recovers.
|10. DRUG INTERACTIONS|
The risks of using quetiapine in combination with other drugs have not been extensively evaluated in systematic studies. Given the primary CNS effects of quetiapine, caution should be used when it is taken in combination with other centrally acting drugs. Quetiapine potentiated the cognitive and motor effects of alcohol in a clinical trial in subjects with selected psychotic disorders, and alcoholic beverages should be avoided while taking quetiapine.
Because of its potential for inducing hypotension, quetiapine may enhance the effects of certain antihypertensive agents.
Quetiapine may antagonize the effects of levodopa and dopamine agonists.
10.1 The Effect of Other Drugs on Quetiapine
Phenytoin: Coadministration of quetiapine (250 mg three times daily) and phenytoin (100 mg three times daily) increased the mean oral clearance of quetiapine by 5-fold. Increased doses of quetiapine may be required to maintain control of symptoms of schizophrenia in patients receiving quetiapine and phenytoin, or other hepatic enzyme inducers (e.g., carbamazepine, barbiturates, rifampin, glucocorticoids). Caution should be taken if phenytoin is withdrawn and replaced with a non-inducer (e.g., valproate) [see Dosage and Administration].
Divalproex: Coadministration of quetiapine (150 mg twice daily) and divalproex (500 mg twice daily) increased the mean maximum plasma concentration of quetiapine at steady state by 17% without affecting the extent of absorption or mean oral clearance.
Thioridazine: Thioridazine (200 mg twice daily) increased the oral clearance of quetiapine (300 mg twice daily) by 65%.
Cimetidine: Administration of multiple daily doses of cimetidine (400 mg three times daily for 4 days) resulted in a 20% decrease in the mean oral clearance of quetiapine (150 mg three times daily). Dosage adjustment for quetiapine is not required when it is given with cimetidine.
P450 3A Inhibitors: Coadministration of ketoconazole (200 mg once daily for 4 days), a potent inhibitor of cytochrome P450 3A, reduced oral clearance of quetiapine by 84%, resulting in a 335% increase in maximum plasma concentration of quetiapine. Caution (reduced dosage) is indicated when quetiapine is administered with ketoconazole and other inhibitors of cytochrome P450 3A (e.g., itraconazole, fluconazole, erythromycin, and protease inhibitors).
Fluoxetine, Imipramine, Haloperidol, and Risperidone: Coadministration of fluoxetine (60 mg once daily), imipramine (75 mg twice daily), haloperidol (7.5 mg twice daily), or risperidone (3 mg twice daily) with quetiapine (300 mg twice daily) did not alter the steady-state pharmacokinetics of quetiapine.
10.2 Effect of Quetiapine on Other Drugs
Lorazepam: The mean oral clearance of lorazepam (2 mg, single dose) was reduced by 20% in the presence of quetiapine administered as 250 mg three times daily dosing.
Divalproex: The mean maximum concentration and extent of absorption of total and free valproic acid at steady state were decreased by 10 to 12% when divalproex (500 mg twice daily) was administered with quetiapine (150 mg twice daily). The mean oral clearance of total valproic acid (administered as divalproex 500 mg twice daily) was increased by 11% in the presence of quetiapine (150 mg twice daily). The changes were not significant.
Lithium: Concomitant administration of quetiapine (250 mg three times daily) with lithium had no effect on any of the steady-state pharmacokinetic parameters of lithium.
Antipyrine: Administration of multiple daily doses up to 750 mg/day (on a three times daily schedule) of quetiapine to subjects with selected psychotic disorders had no clinically relevant effect on the clearance of antipyrine or urinary recovery of antipyrine metabolites. These results indicate that quetiapine does not significantly induce hepatic enzymes responsible for cytochrome P450 mediated metabolism of antipyrine.
Quetiapine fumarate activity is primarily due to the parent drug. The multiple-dose pharmacokinetics of quetiapine are dose-proportional within the proposed clinical dose range, and quetiapine accumulation is predictable upon multiple dosing. Elimination of quetiapine is mainly via hepatic metabolism with a mean terminal half-life of about 6 hours within the proposed clinical dose range. Steady-state concentrations are expected to be achieved within two days of dosing. Quetiapine is unlikely to interfere with the metabolism of drugs metabolized by cytochrome P450 enzymes.
Quetiapine fumarate is rapidly absorbed after oral administration, reaching peak plasma concentrations in 1.5 hours. The tablet formulation is 100% bioavailable relative to solution. The bioavailability of quetiapine is marginally affected by administration with food, with Cmax and AUC values increased by 25% and 15%, respectively.
Quetiapine is widely distributed throughout the body with an apparent volume of distribution of 10±4 L/kg. It is 83% bound to plasma proteins at therapeutic concentrations. In vitro, quetiapine did not affect the binding of warfarin or diazepam to human serum albumin. In turn, neither warfarin nor diazepam altered the binding of quetiapine.
Metabolism and Elimination
Following a single oral dose of 14C-quetiapine, less than 1% of the administered dose was excreted as unchanged drug, indicating that quetiapine is highly metabolized. Approximately 73% and 20% of the dose was recovered in the urine and feces, respectively. Quetiapine is extensively metabolized by the liver. The major metabolic pathways are sulfoxidation to the sulfoxide metabolite and oxidation to the parent acid metabolite; both metabolites are pharmacologically inactive. In vitro studies using human liver microsomes revealed that the cytochrome P450 3A4 isoenzyme is involved in the metabolism of quetiapine to its major, but inactive, sulfoxide metabolite and in the metabolism of its active metabolite N-desalkyl quetiapine.
Age: Oral clearance of quetiapine was reduced by 40% in elderly patients (≥65 years, n=9) compared to young patients (n=12), and dosing adjustment may be necessary [see Dosage and Administration].
Gender: There is no gender effect on the pharmacokinetics of quetiapine.
Race: There is no race effect on the pharmacokinetics of quetiapine.
Smoking: Smoking has no effect on the oral clearance of quetiapine.
Renal Insufficiency: Patients with severe renal impairment (Clcr=10-30 mL/min/1.73 m2, n=8) had a 25% lower mean oral clearance than normal subjects (Clcr >80 mL/min/1.73 m2, n=8), but plasma quetiapine concentrations in the subjects with renal insufficiency were within the range of concentrations seen in normal subjects receiving the same dose. Dosage adjustment is therefore not needed in these patients.
Hepatic Insufficiency: Hepatically impaired patients (n=8) had a 30% lower mean oral clearance of quetiapine than normal subjects. In two of the 8 hepatically impaired patients, AUC and Cmax were 3 times higher than those observed typically in healthy subjects. Since quetiapine is extensively metabolized by the liver, higher plasma levels are expected in the hepatically impaired population, and dosage adjustment may be needed [see Dosage and Administration].
|12. HOW SUPPLIED/STORAGE AND HANDLING|
1) How Available:
a) Brand name: SEROQUEL, by ASTRAZENECA.
b) Generic drugs: Quetiapine fumarate, by various manufacturers.
2) How Supplied:
Quetiapine fumarate tablets (by Dr. Reddy's Labs) are available as 25 mg, white, round, biconvex, film coated tablets debossed with ‘R’ on one side and ‘1’ on other side and they are supplied in bottles of 30’s, 60’s,100’s, 500’s and unit dose package of 100 (10 x 10).
Bottles of 30 NDC 55111-249-30
Bottles of 60 NDC 55111-249-60
Bottles of 100 NDC 55111-249-01
Bottles of 500 NDC 55111-249-05
Unit dose package of 100 (10 x 10) NDC 55111-249-78
Quetiapine fumarate tablets 50 mg are white colored, round, biconvex, film coated tablets, debossed with ‘R’ on one side and ‘2’ on other side and they are supplied in bottles of 30’s, 60’s,100’s, 500’s and unit dose package of 100 (10 x 10).
Bottles of 30 NDC 55111-169-30
Bottles of 60 NDC 55111-169-60
Bottles of 100 NDC 55111-169-01
Bottles of 500 NDC 55111-169-05
Unit dose package of 100 (10 x 10) NDC 55111-169-78
Quetiapine fumarate tablets 100 mg are yellow colored, round, biconvex, film coated tablets debossed with ‘R’ on one side and ‘3’ on other side and they are supplied in bottles of 30’s, 60’s,100’s, 500’s and unit dose package of 100 (10 x 10).
Bottles of 30 NDC 55111-186-30
Bottles of 60 NDC 55111-186-60
Bottles of 100 NDC 55111-186-01
Bottles of 500 NDC 55111-186-05
Unit dose package of 100 (10 x 10) NDC 55111-186-78
Quetiapine fumarate tablets 150 mg are yellow colored, round, biconvex, film coated tablets debossed with ‘RDY’ on one side and ‘188’ on other side and they are supplied in bottles of 30’s, 60’s,100’s, 500’s and unit dose package of 100 (10 x 10).
Bottles of 30 NDC 55111-188-30
Bottles of 60 NDC 55111-188-60
Bottles of 100 NDC 55111-188-01
Bottles of 500 NDC 55111-188-05
Unit dose package of 100 (10 x 10) NDC 55111-188-78
Quetiapine fumarate tablets 200 mg are white, round, biconvex, film coated tablets, debossed with ‘R’ on one side and ‘5’ on other side and they are supplied in bottles of 30’s, 60’s,100’s, 500’s and unit dose package of 100 (10 x 10).
Bottles of 30 NDC 55111-189-30
Bottles of 60 NDC 55111-189-60
Bottles of 100 NDC 55111-189-01
Bottles of 500 NDC 55111-189-05
Unit dose package of 100 (10 x 10) NDC 55111-189-78
Quetiapine fumarate tablets 300 mg are white colored, modified capsule shaped, biconvex, film coated tablets, debossed with ‘R’ on one side and ‘6’ on other side and they are supplied in bottles of 30’s, 60’s,100’s, 500’s and unit dose package of 100 (10 x 10).
Bottles of 30 NDC 55111-190-30
Bottles of 60 NDC 55111-190-60
Bottles of 100 NDC 55111-190-01
Bottles of 500 NDC 55111-190-05
Unit dose package of 100 (10 x 10) NDC 55111-190-78
Quetiapine fumarate tablets 400 mg are yellow colored, capsule shaped, biconvex, film coated tablets, debossed with ‘R' on one side and ‘7’ on other side and they are supplied in bottles of 30’s, 60’s,100’s, 500’s and unit dose package of 100 (10 x 10).
Bottles of 30 NDC 55111-606-30
Bottles of 60 NDC 55111-606-60
Bottles of 100 NDC 55111-606-01
Bottles of 500 NDC 55111-606-05
Unit dose package of 100 (10 x 10) NDC 55111-606-78
3) Storage: Store at 25°C (77°F). Excursions permitted to 15-30°C (59-86°F).