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Enoxaparin Sodium Injection

For Subcutaneous (SC) and Intravenous (IV) Use

TABLE OF CONTENTS

1. DESCRIPTION 7. WARNINGS AND PRECAUTIONS
2. INDICATIONS AND USAGE 8. ADVERSE REACTIONS
3. DOSAGE AND ADMINISTRATION 9. OVERDOSAGE
4. CONTRAINDICATIONS 10. DRUG INTERACTIONS
5. MECHANISM OF ACTION 11. PHARMACOKINETICS
6. USE IN SPECIFIC POPULATIONS 12. HOW SUPPLIED/STORAGE AND HANDLING

 


WARNING: SPINAL/EPIDURAL HEMATOMAS

Epidural or spinal hematomas may occur in patients who are anticoagulated with low molecular weight heparins (LMWH) or heparinoids and are receiving neuraxial anesthesia or undergoing spinal puncture. These hematomas may result in long-term or permanent paralysis. Consider these risks when scheduling patients for spinal procedures. Factors that can increase the risk of developing epidural or spinal hematomas in these patients include:

• Use of indwelling epidural catheters

• Concomitant use of other drugs that affect hemostasis, such as non-steroidal anti-inflammatory drugs (NSAIDs), platelet inhibitors, other anticoagulants.

• A history of traumatic or repeated epidural or spinal punctures

• A history of spinal deformity or spinal surgery

Monitor patients frequently for signs and symptoms of neurological impairment. If neurological compromise is noted, urgent treatment is necessary.

Consider the benefits and risks before neuraxial intervention in patients anticoagulated or to be anticoagulated for thromboprophylaxis [see Warnings and Precautions and Drug Interactions].


 

1. DESCRIPTION

Enoxaparin sodium is a low molecular weight heparin (LMWH). It is also known as fractionated heparin.

Enoxaparin sodium is obtained by alkaline depolymerization of heparin benzyl ester derived from porcine intestinal mucosa. Its structure is characterized by a 2-O-sulfo-4-enepyranosuronic acid group at the non-reducing end and a 2-N,6-O-disulfo-D-glucosamine at the reducing end of the chain. About 20% (ranging between 15% and 25%) of the enoxaparin structure contains an 1,6 anhydro derivative on the reducing end of the polysaccharide chain. The structural formula is:

 

* X = Percent of polysaccharide chain containing 1,6 anhydro derivative on the reducing end.

The drug substance is the sodium salt. The average molecular weight is about 4500 daltons. The molecular weight distribution is:

< 2000 daltons ≤ 20%
2000 to 8000 daltons ≥ 68%
> 8000 daltons ≤ 18%

 

2. INDICATIONS AND USAGE

2.1 Prophylaxis of Deep Vein Thrombosis (DVT)

Enoxaparin is indicated for the prophylaxis of deep vein thrombosis, which may lead to pulmonary embolism (PE):

• in patients undergoing abdominal surgery who are at risk for thromboembolic complications.

• in patients undergoing hip replacement surgery, during and following hospitalization.

• in patients undergoing knee replacement surgery.

• in medical patients who are at risk for thromboembolic complications due to severely restricted mobility during acute illness.

2.2 Treatment of Acute Deep Vein Thrombosis

Enoxaparin is indicated for:

• the inpatient treatment of acute deep vein thrombosis with or without pulmonary embolism, when administered in conjunction with warfarin sodium.

• the outpatient treatment of acute deep vein thrombosis without pulmonary embolism when administered in conjunction with warfarin sodium.

2.3 Prophylaxis of Ischemic Complications of Unstable Angina and Non-Q-Wave Myocardial Infarction

Enoxaparin is indicated for the prophylaxis of ischemic complications of unstable angina and nonQ-wave myocardial infarction, when concurrently administered with aspirin.

2.4 Treatment of Acute ST-Segment Elevation Myocardial Infarction

Enoxaparin, when administered concurrently with aspirin, has been shown to reduce the rate of the combined endpoint of recurrent myocardial infarction or death in patients with acute ST-segment elevation myocardial infarction (STEMI) receiving thrombolysis and being managed medically or with percutaneous coronary intervention (PCI).

3. DOSAGE AND ADMINISTRATION

All patients should be evaluated for a bleeding disorder before administration of enoxaparin, unless the medication is needed urgently. Since coagulation parameters are unsuitable for monitoring enoxaparin activity, routine monitoring of coagulation parameters is not required [see Warnings and Precautions].

For subcutaneous use, enoxaparin should not be mixed with other injections or infusions. For intravenous use (i.e., for treatment of acute STEMI), enoxaparin can be mixed with normal saline solution (0.9%) or 5% dextrose in water.

Enoxaparin is not intended for intramuscular administration.

3.1 Adult Dosage

Abdominal Surgery: In patients undergoing abdominal surgery who are at risk for thromboembolic complications, the recommended dose of enoxaparin is 40 mg once a day administered by SC injection with the initial dose given 2 hours prior to surgery. The usual duration of administration is 7 to 10 days; up to 12 days administration has been administered in clinical trials.

Hip or Knee Replacement Surgery: In patients undergoing hip or knee replacement surgery, the recommended dose of enoxaparin is 30 mg every 12 hours administered by SC injection. Provided that hemostasis has been established, the initial dose should be given 12 to 24 hours after surgery. For hip replacement surgery, a dose of 40 mg once a day SC, given initially 12 (±3) hours prior to surgery, may be considered. Following the initial phase of thromboprophylaxis in hip replacement surgery patients, it is recommended that continued prophylaxis with enoxaparin 40 mg once a day be administered by SC injection for 3 weeks. The usual duration of administration is 7 to 10 days; up to 14 days administration has been administered in clinical trials.

Medical Patients During Acute Illness: In medical patients at risk for thromboembolic complications due to severely restricted mobility during acute illness, the recommended dose of enoxaparin is 40 mg once a day administered by SC injection. The usual duration of administration is 6 to 11 days; up to 14 days of enoxaparin has been administered in the controlled clinical trial.

Treatment of Deep Vein Thrombosis with or without Pulmonary Embolism: In outpatient treatment, patients with acute deep vein thrombosis without pulmonary embolism who can be treated at home, the recommended dose of enoxaparin is 1 mg/kg every 12 hours administered SC. In inpatient (hospital) treatment, patients with acute deep vein thrombosis with pulmonary embolism or patients with acute deep vein thrombosis without pulmonary embolism (who are not candidates for outpatient treatment), the recommended dose of enoxaparin is 1 mg/kg every 12 hours administered SC or 1.5 mg/kg once a day administered SC at the same time every day. In both outpatient and inpatient (hospital) treatments, warfarin sodium therapy should be initiated when appropriate (usually within 72 hours of enoxaparin). Enoxaparin should be continued for a minimum of 5 days and until a therapeutic oral anticoagulant effect has been achieved (International Normalization Ratio 2.0 to 3.0). The average duration of administration is 7 days; up to 17 days of enoxaparin administration has been administered in controlled clinical trials.

Unstable Angina and Non-Q-Wave Myocardial Infarction: In patients with unstable angina or non-Q-wave myocardial infarction, the recommended dose of enoxaparin is 1 mg/kg administered SC every 12 hours in conjunction with oral aspirin therapy (100 to 325 mg once daily). Treatment with enoxaparin should be prescribed for a minimum of 2 days and continued until clinical stabilization. The usual duration of treatment is 2 to 8 days; up to 12.5 days of enoxaparin has been administered in clinical trials [see Warnings and Precautions].

Treatment of Acute ST-Segment Elevation Myocardial Infarction: In patients with acute ST-segment elevation myocardial infarction, the recommended dose of enoxaparin is a single IV bolus of 30 mg plus a 1 mg/kg SC dose followed by 1 mg/kg administered SC every 12 hours (maximum 100 mg for the first two doses only, followed by 1 mg/kg dosing for the remaining doses). Dosage adjustments are recommended in patients ≥75 years of age [see Dosage and Administration (2.3)]. All patients should receive aspirin as soon as they are identified as having STEMI and maintained with 75 to 325 mg once daily unless contraindicated.

When administered in conjunction with a thrombolytic (fibrin-specific or non-fibrin specific), enoxaparin should be given between 15 minutes before and 30 minutes after the start of fibrinolytic therapy. In the pivotal clinical study, the enoxaparin treatment duration was 8 days or until hospital discharge, whichever came first. An optimal duration of treatment is not known, but it is likely to be longer than 8 days.

For patients managed with percutaneous coronary intervention (PCI): If the last enoxaparin SC administration was given less than 8 hours before balloon inflation, no additional dosing is needed. If the last enoxaparin SC administration was given more than 8 hours before balloon inflation, an IV bolus of 0.3 mg/kg of enoxaparin should be administered [see Warnings and Precautions].

3.2 Renal Impairment

Although no dose adjustment is recommended in patients with moderate (creatinine clearance 30-50 mL/min) and mild (creatinine clearance 50-80 mL/min) renal impairment, all such patients should be observed carefully for signs and symptoms of bleeding.

The recommended prophylaxis and treatment dosage regimens for patients with severe renal impairment (creatinine clearance < 30 mL/min) are described in Table 1 [see Use in Specific Populations].

Table 1: Dosage Regimens for Patients with Severe Renal Impairment (creatinine clearance < 30mL/minute)

3.3 Geriatric Patients with Acute ST-Segment Elevation Myocardial Infarction

For treatment of acute ST-segment elevation myocardial infarction in geriatric patients ≥75 years of age, do not use an initial IV bolus. Initiate dosing with 0.75 mg/kg SC every 12 hours (maximum 75 mg for the first two doses only, followed by 0.75 mg/kg dosing for the remaining doses) [see Use in Specific Populations].

No dose adjustment is necessary for other indications in geriatric patients unless kidney function is impaired [see Dosage and Administration].

3.4 Administration

Enoxaparin is a clear, colorless to pale yellow sterile solution, and as with other parenteral drug products, should be inspected visually for particulate matter and discoloration prior to administration.

The use of a tuberculin syringe or equivalent is recommended when using enoxaparin multiple-dose vials to assure withdrawal of the appropriate volume of drug.

Enoxaparin must not be administered by intramuscular injection. Enoxaparin is intended for use under the guidance of a physician.

For subcutaneous administration, patients may self-inject only if their physicians determine that it is appropriate and with medical follow-up, as necessary. Proper training in subcutaneous injection technique (with or without the assistance of an injection device) should be provided.

Subcutaneous Injection Technique: Patients should be lying down and enoxaparin administered by deep SC injection. To avoid the loss of drug when using the 30 and 40 mg prefilled syringes, do not expel the air bubble from the syringe before the injection. Administration should be alternated between the left and right anterolateral and left and right posterolateral abdominal wall. The whole length of the needle should be introduced into a skin fold held between the thumb and forefinger; the skin fold should be held throughout the injection. To minimize bruising, do not rub the injection site after completion of the injection.

Enoxaparin prefilled syringes and graduated prefilled syringes are for single, one-time use only and are available with a system that shields the needle after injection.

Remove the prefilled syringe from the blister packaging by peeling at the arrow as directed on the blister. Do not remove by pulling on the plunger as this may damage the syringe.

1. Remove the needle shield by pulling it straight off the syringe (see Figure 1). If adjusting the dose is required, the dose adjustment must be done prior to injecting the prescribed dose to the patient.

Figure 1.

2. Inject using standard technique, pushing the plunger to the bottom of the syringe (see Figure 2).

Figure 2.

3. Remove the syringe from the injection site keeping your finger on the plunger rod (see Figure 3).

Figure 3.

4. Orient the needle away from you and others, and activate the safety system by firmly pushing the plunger rod. The protective sleeve will automatically cover the needle and an audible “click” will be heard to confirm shield activation (see Figure 4).

Figure 4.

5. Immediately dispose of the syringe in the nearest sharps container (see Figure 5).

Figure 5.

NOTE:

• The safety system can only be activated once the syringe has been emptied.

• Activation of the safety system must be done only after removing the needle from the patient’s skin.

• Do not replace the needle shield after injection.

• The safety system should not be sterilized.

Activation of the safety system may cause minimal splatter of fluid. For optimal safety activate the system while orienting it downwards away from yourself and others.

Intravenous (Bolus) Injection Technique: For intravenous injection, the multiple-dose vial should be used. Enoxaparin should be administered through an intravenous line. Enoxaparin should not be mixed or co-administered with other medications. To avoid the possible mixture of enoxaparin with other drugs, the intravenous access chosen should be flushed with a sufficient amount of saline or dextrose solution prior to and following the intravenous bolus administration of enoxaparin to clear the port of drug. Enoxaparin may be safely administered with normal saline solution (0.9%) or 5% dextrose in water.

4. CONTRAINDICATIONS

• Active major bleeding

• Thrombocytopenia associated with a positive in vitro test for anti-platelet antibody in the presence of enoxaparin sodium

• Known hypersensitivity to enoxaparin sodium (e.g., pruritus, urticaria, anaphylactic/anaphylactoid reactions) [see Adverse Reactions]

• Known hypersensitivity to heparin or pork products

• Known hypersensitivity to benzyl alcohol (which is in only the multi-dose formulation of enoxaparin) [see Warnings and Precautions].

5. MECHANISM OF ACTION

Enoxaparin is a low molecular weight heparin which has antithrombotic properties.

6. USE IN SPECIFIC POPULATIONS

6.1 Usage in Pregnancy

Pregnancy Category B

All pregnancies have a background risk of birth defect, loss, or other adverse outcome regardless of drug exposure. The fetal risk summary below describes the potential of enoxaparin to increase the risk of developmental abnormalities above the background risk.

Fetal Risk Summary

Enoxaparin does not cross the placenta, and is not expected to result in fetal exposure to the drug. Human data from a retrospective cohort study, which included 693 live births, suggest that enoxaparin does not increase the risk of major developmental abnormalities. Based on animal data, enoxaparin is not predicted to increase the risk of major developmental abnormalities (see Data).

Clinical Considerations

Pregnancy alone confers an increased risk for thromboembolism that is even higher for women with thromboembolic disease and certain high risk pregnancy conditions. While not adequately studied, pregnant women with mechanical prosthetic heart valves may be at even higher risk for thrombosis [see Warnings and Precautions and Use in Specific Populations]. Pregnant women with thromboembolic disease, including those with mechanical prosthetic heart valves and those with inherited or acquired thrombophilias, have an increased risk of other maternal complications and fetal loss regardless of the type of anticoagulant used.

All patients receiving anticoagulants, including pregnant women, are at risk for bleeding. Pregnant women receiving enoxaparin should be carefully monitored for evidence of bleeding or excessive anticoagulation. Consideration for use of a shorter acting anticoagulant should be specifically addressed as delivery approaches [see Boxed Warning]. Hemorrhage can occur at any site and may lead to death of mother and/or fetus. Pregnant women should be apprised of the potential hazard to the fetus and the mother if enoxaparin is administered during pregnancy.

It is not known if monitoring of anti-Factor Xa activity and dose adjustment (by weight or anti-Factor Xa activity) of enoxaparin affect the safety and the efficacy of the drug during pregnancy.

Cases of “gasping syndrome” have occurred in premature infants when large amounts of benzyl alcohol have been administered (99-405 mg/kg/day). The multiple-dose vial of enoxaparin contains 15 mg benzyl alcohol per 1 mL as a preservative [see Warnings and Precautions].

Data

Human Data -There are no adequate and well-controlled studies in pregnant women. A retrospective study reviewed the records of 604 women who used enoxaparin during pregnancy. A total of 624 pregnancies resulted in 693 live births. There were 72 hemorrhagic events (11 serious) in 63 women. There were 14 cases of neonatal hemorrhage. Major congenital anomalies in live births occurred at rates (2.5%) similar to background rates.

There have been postmarketing reports of fetal death when pregnant women received enoxaparin. Causality for these cases has not been determined. Insufficient data, the underlying disease, and the possibility of inadequate anticoagulation complicate the evaluation of these cases.

A clinical study using enoxaparin in pregnant women with mechanical prosthetic heart valves has been conducted [see Warnings and Precautions].

6.2 Nursing Mothers

It is not known whether enoxaparin is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from enoxaparin, a decision should be made whether to discontinue nursing or discontinue enoxaparin, taking into account the importance of enoxaparin to the mother and the known benefits of nursing.

6.3 Pediatric Use

Safety and effectiveness of enoxaparin in pediatric patients have not been established.

6.4 Geriatric Use

Prevention of Deep Vein Thrombosis in Hip, Knee and Abdominal Surgery; Treatment of Deep Vein Thrombosis, Prevention of Ischemic Complications of Unstable Angina and Non-Q-wave Myocardial Infarction

Over 2800 patients, 65 years and older, have received enoxaparin in pivotal clinical trials. The efficacy of enoxaparin in the geriatric (≥ 65 years) was similar to that seen in younger patients (< 65 years). The incidence of bleeding complications was similar between geriatric and younger patients when 30 mg every 12 hours or 40 mg once a day doses of enoxaparin were employed. The incidence of bleeding complications was higher in geriatric patients as compared to younger patients when enoxaparin was administered at doses of 1.5 mg/kg once a day or 1 mg/kg every 12 hours. The risk of enoxaparin-associated bleeding increased with age. Serious adverse events increased with age for patients receiving enoxaparin. Other clinical experience (including postmarketing surveillance and literature reports) has not revealed additional differences in the safety of enoxaparin between geriatric and younger patients. Careful attention to dosing intervals and concomitant medications (especially antiplatelet medications) is advised. Enoxaparin should be used with care in geriatric patients who may show delayed elimination of enoxaparin. Monitoring of geriatric patients with low body weight (< 45 kg) and those predisposed to decreased renal function should be considered [see Warnings and Precautions].

Treatment of Acute ST-Segment Elevation Myocardial Infarction

In the clinical study for treatment of acute ST-segment elevation myocardial infarction, there was no evidence of difference in efficacy between patients ≥75 years of age (n = 1241) and patients less than 75 years of age (n=9015). Patients ≥75 years of age did not receive a 30 mg IV bolus prior to the normal dosage regimen and had their SC dose adjusted to 0.75 mg/kg every 12 hours [see Dosage and Administration]. The incidence of bleeding complications was higher in patients ≥65 years of age as compared to younger patients (< 65 years).

6.5 Patients with Mechanical Prosthetic Heart Valves

The use of enoxaparin has not been adequately studied for thromboprophylaxis in patients with mechanical prosthetic heart valves and has not been adequately studied for long-term use in this patient population. Isolated cases of prosthetic heart valve thrombosis have been reported in patients with mechanical prosthetic heart valves who have received enoxaparin for thromboprophylaxis. Some of these cases were pregnant women in whom thrombosis led to maternal and fetal deaths. Insufficient data, the underlying disease and the possibility of inadequate anticoagulation complicate the evaluation of these cases. Pregnant women with mechanical prosthetic heart valves may be at higher risk for thromboembolism [see Warnings and Precautions].

6.6 Renal Impairment

In patients with renal impairment, there is an increase in exposure of enoxaparin sodium. All such patients should be observed carefully for signs and symptoms of bleeding. Because exposure of enoxaparin sodium is significantly increased in patients with severe renal impairment (creatinine clearance < 30 mL/min), a dosage adjustment is recommended for therapeutic and prophylactic dosage ranges. No dosage adjustment is recommended in patients with moderate (creatinine clearance 30-50 mL/min) and mild (creatinine clearance 50-80 mL/min) renal impairment [see Dosage and Administration]. In patients with renal failure, treatment with enoxaparin has been associated with the development of hyperkalemia [see Adverse Reactions].

6.7 Hepatic Impairment

The impact of hepatic impairment on enoxaparin’s exposure and antithrombotic effect has not been investigated. Caution should be exercised when administering enoxaparin to patients with hepatic impairment.

6.8 Low-Weight Patients

An increase in exposure of enoxaparin sodium with prophylactic dosages (non-weight adjusted) has been observed in low-weight women (< 45 kg) and low-weight men (< 57 kg). All such patients should be observed carefully for signs and symptoms of bleeding.

7. WARNINGS AND PRECAUTIONS

7.1 Increased Risk of Hemorrhage

Cases of epidural or spinal hematomas have been reported with the associated use of enoxaparin and spinal/epidural anesthesia or spinal puncture resulting in long-term or permanent paralysis. The risk of these events is higher with the use of post-operative indwelling epidural catheters, with the concomitant use of additional drugs affecting hemostasis such as NSAIDs, with traumatic or repeated epidural or spinal puncture, or in patients with a history of spinal surgery or spinal deformity [see Boxed Warning, Adverse Reactions and Drug Interactions].

Enoxaparin should be used with extreme caution in conditions with increased risk of hemorrhage, such as bacterial endocarditis, congenital or acquired bleeding disorders, active ulcerative and angiodysplastic gastrointestinal disease, hemorrhagic stroke, or shortly after brain, spinal, or ophthalmological surgery, or in patients treated concomitantly with platelet inhibitors.

Major hemorrhages including retroperitoneal and intracranial bleeding have been reported. Some of these cases have been fatal.

Bleeding can occur at any site during therapy with enoxaparin. An unexplained fall in hematocrit or blood pressure should lead to a search for a bleeding site.

7.2 Percutaneous Coronary Revascularization Procedures

To minimize the risk of bleeding following the vascular instrumentation during the treatment of unstable angina, non-Q-wave myocardial infarction and acute ST-segment elevation myocardial infarction, adhere precisely to the intervals recommended between enoxaparin doses. It is important to achieve hemostasis at the puncture site after PCI. In case a closure device is used, the sheath can be removed immediately. If a manual compression method is used, sheath should be removed 6 hours after the last IV/SC enoxaparin. If the treatment with enoxaparin sodium is to be continued, the next scheduled dose should be given no sooner than 6 to 8 hours after sheath removal. The site of the procedure should be observed for signs of bleeding or hematoma formation [see Dosage and Administration].

7.3 Use of Enoxaparin with Concomitant Medical Conditions

Enoxaparin should be used with care in patients with a bleeding diathesis, uncontrolled arterial hypertension or a history of recent gastrointestinal ulceration, diabetic retinopathy, renal dysfunction and hemorrhage.

7.4 History of Heparin-Induced Thrombocytopenia

Enoxaparin should be used with extreme caution in patients with a history of heparin-induced thrombocytopenia.

7.5 Thrombocytopenia

Thrombocytopenia can occur with the administration of enoxaparin.

Moderate thrombocytopenia (platelet counts between 100,000/mm3 and 50,000/mm3) occurred at a rate of 1.3% in patients given enoxaparin, 1.2% in patients given heparin, and 0.7% in patients given placebo in clinical trials.

Platelet counts less than 50,000/mm3 occurred at a rate of 0.1% in patients given enoxaparin, in 0.2% of patients given heparin, and 0.4% of patients given placebo in the same trials.

Thrombocytopenia of any degree should be monitored closely. If the platelet count falls below 100,000/mm3, enoxaparin should be discontinued. Cases of heparin-induced thrombocytopenia with thrombosis have also been observed in clinical practice. Some of these cases were complicated by organ infarction, limb ischemia, or death [see Warnings and Precautions].

7.6 Interchangeability with Other Heparins

Enoxaparin cannot be used interchangeably (unit for unit) with heparin or other low molecular weight heparins as they differ in manufacturing process, molecular weight distribution, anti-Xa and anti-IIa activities, units, and dosage. Each of these medicines has its own instructions for use.

7.7 Pregnant Women with Mechanical Prosthetic Heart Valves

The use of enoxaparin for thromboprophylaxis in pregnant women with mechanical prosthetic heart valves has not been adequately studied. In a clinical study of pregnant women with mechanical prosthetic heart valves given enoxaparin (1 mg/kg twice daily) to reduce the risk of thromboembolism, 2 of 8 women developed clots resulting in blockage of the valve and leading to maternal and fetal death. Although a causal relationship has not been established these deaths may have been due to therapeutic failure or inadequate anticoagulation. No patients in the heparin/warfarin group (0 of 4 women) died. There also have been isolated postmarketing reports of valve thrombosis in pregnant women with mechanical prosthetic heart valves while receiving enoxaparin for thromboprophylaxis. Women with mechanical prosthetic heart valves may be at higher risk for thromboembolism during pregnancy, and, when pregnant, have a higher rate of fetal loss from stillbirth, spontaneous abortion and premature delivery. Therefore, frequent monitoring of peak and trough anti-Factor Xa levels, and adjusting of dosage may be needed [see Use in Specific Populations].

7.8 Benzyl Alcohol

Enoxaparin multiple-dose vials contain benzyl alcohol as a preservative. The administration of medications containing benzyl alcohol as a preservative to premature neonates has been associated with a fatal “gasping syndrome”. Because benzyl alcohol may cross the placenta, enoxaparin multiple-dose vials, preserved with benzyl alcohol, should be used with caution in pregnant women and only if clearly needed [see Use in Specific Populations].

7.9 Laboratory Tests

Periodic complete blood counts, including platelet count, and stool occult blood tests are recommended during the course of treatment with enoxaparin. When administered at recommended prophylaxis doses, routine coagulation tests such as Prothrombin Time (PT) and Activated Partial Thromboplastin Time (aPTT) are relatively insensitive measures of enoxaparin activity and, therefore, unsuitable for monitoring. Anti-Factor Xa may be used to monitor the anticoagulant effect of enoxaparin in patients with significant renal impairment. If during enoxaparin therapy abnormal coagulation parameters or bleeding should occur, anti-Factor Xa levels may be used to monitor the anticoagulant effects of enoxaparin.

8. ADVERSE REACTIONS

8.1 Clinical Trials Experience

The following serious adverse reactions are also discussed in other sections of the labeling:

• Spinal/epidural hematoma [see Boxed Warning and Warnings and Precautions]

• Increased Risk of Hemorrhage [see Warnings and Precautions]

• Thrombocytopenia [see Warnings and Precautions]

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.

During clinical development for the approved indications, 15,918 patients were exposed to enoxaparin sodium. These included 1,228 for prophylaxis of deep vein thrombosis following abdominal surgery in patients at risk for thromboembolic complications, 1,368 for prophylaxis of deep vein thrombosis following hip or knee replacement surgery, 711 for prophylaxis of deep vein thrombosis in medical patients with severely restricted mobility during acute illness, 1,578 for prophylaxis of ischemic complications in unstable angina and non-Q-wave myocardial infarction, 10,176 for treatment of acute ST-elevation myocardial infarction, and 857 for treatment of deep vein thrombosis with or without pulmonary embolism. Enoxaparin sodium doses in the clinical trials for prophylaxis of deep vein thrombosis following abdominal or hip or knee replacement surgery or in medical patients with severely restricted mobility during acute illness ranged from 40 mg SC once daily to 30 mg SC twice daily. In the clinical studies for prophylaxis of ischemic complications of unstable angina and non-Q-wave myocardial infarction doses were 1 mg/kg every 12 hours and in the clinical studies for treatment of acute ST-segment elevation myocardial infarction enoxaparin sodium doses were a 30 mg IV bolus followed by 1 mg/kg every 12 hours SC.

Hemorrhage

The incidence of major hemorrhagic complications during enoxaparin treatment has been low.

The following rates of major bleeding events have been reported during clinical trials with enoxaparin [see Tables 2 to 7].

Table 2: Major Bleeding Episodes Following Abdominal and Colorectal Surgery1

1 Bleeding complications were considered major: (1) if the hemorrhage caused a significant clinical event, or (2) if accompanied by a hemoglobin decrease ≥ 2 g/dL or transfusion of 2 or more units of blood products. Retroperitoneal, intraocular, and intracranial hemorrhages were always considered major.

Table 3: Major Bleeding Episodes Following Hip or Knee Replacement Surgery1

1 Bleeding complications were considered major: (1) if the hemorrhage caused a significant clinical event, or (2) if accompanied by a hemoglobin decrease ≥ 2 g/dL or transfusion of 2 or more units of blood products. Retroperitoneal and intracranial hemorrhages were always considered major. In the knee replacement surgery trials, intraocular hemorrhages were also considered major hemorrhages.

2 Enoxaparin 30 mg every 12 hours SC initiated 12 to 24 hours after surgery and continued for up to 14 days after surgery

3 Enoxaparin 40 mg SC once a day initiated up to 12 hours prior to surgery and continued for up to 7 days after surgery

4 Enoxaparin 40 mg SC once a day for up to 21 days after discharge

NOTE: At no time point were the 40 mg once a day pre-operative and the 30 mg every 12 hours post-operative hip replacement surgery prophylactic regimens compared in clinical trials. Injection site hematomas during the extended prophylaxis period after hip replacement surgery occurred in 9% of the enoxaparin patients versus 1.8% of the placebo patients.

Table 4: Major Bleeding Episodes in Medical Patients with Severely Restricted Mobility During Acute Illness1

1 Bleeding complications were considered major: (1) if the hemorrhage caused a significant clinical event, (2) if the hemorrhage caused a decrease in hemoglobin of ≥ 2 g/dL or transfusion of 2 or more units of blood products. Retroperitoneal and intracranial hemorrhages were always considered major although none were reported during the trial.

2 The rates represent major bleeding on study medication up to 24 hours after last dose.

Table 5: Major Bleeding Episodes in Deep Vein Thrombosis with or without Pulmonary Embolism Treatment1

1 Bleeding complications were considered major: (1) if the hemorrhage caused a significant clinical event, or (2) if accompanied by a hemoglobin decrease ≥ 2 g/dL or transfusion of 2 or more units of blood products. Retroperitoneal, intraocular, and intracranial hemorrhages were always considered major.

2 All patients also received warfarin sodium (dose-adjusted according to PT to achieve an INR of 2.0 to 3.0) commencing within 72 hours of enoxaparin or standard heparin therapy and continuing for up to 90 days.

Table 6: Major Bleeding Episodes in Unstable Angina and Non-Q-Wave Myocardial Infarction

1 The rates represent major bleeding on study medication up to 12 hours after dose.

2 Aspirin therapy was administered concurrently (100 to 325 mg per day).

3 Bleeding complications were considered major: (1) if the hemorrhage caused a significant clinical event, or (2) if accompanied by a hemoglobin decrease by ≥ 3 g/dL or transfusion of 2 or more units of blood products. Intraocular, retroperitoneal, and intracranial hemorrhages were always considered major.

Table 7: Major Bleeding Episodes in Acute ST-Segment Elevation Myocardial Infarction

1 The rates represent major bleeding (including ICH) up to 30 days

2 Bleedings were considered major if the hemorrhage caused a significant clinical event associated with a hemoglobin decrease by ≥ 5 g/dL. ICH were always considered major.

Elevations of Serum Aminotransferases

Asymptomatic increases in aspartate (AST [SGOT]) and alanine (ALT [SGPT]) aminotransferase levels greater than three times the upper limit of normal of the laboratory reference range have been reported in up to 6.1% and 5.9% of patients, respectively, during treatment with enoxaparin. Similar significant increases in aminotransferase levels have also been observed in patients and healthy volunteers treated with heparin and other low molecular weight heparins. Such elevations are fully reversible and are rarely associated with increases in bilirubin.

Since aminotransferase determinations are important in the differential diagnosis of myocardial infarction, liver disease, and pulmonary emboli, elevations that might be caused by drugs like enoxaparin should be interpreted with caution.

Local Reactions

Mild local irritation, pain, hematoma, ecchymosis, and erythema may follow SC injection of enoxaparin.

Adverse Reactions in Patients Receiving Enoxaparin for Prophylaxis or Treatment of DVT, PE:

Other adverse reactions that were thought to be possibly or probably related to treatment with enoxaparin, heparin, or placebo in clinical trials with patients undergoing hip or knee replacement surgery, abdominal or colorectal surgery, or treatment for DVT and that occurred at a rate of at least 2% in the enoxaparin group, are provided below [see Tables 8 to 11].

Table 8: Adverse Reactions Occurring at ≥2% Incidence in Enoxaparin-Treated Patients Undergoing Abdominal or Colorectal Surgery

 

Table 9: Adverse Reactions Occurring at ≥2% Incidence in Enoxaparin-Treated Patients Undergoing Hip or Knee Replacement Surgery

1 Data represent enoxaparin 40 mg SC once a day initiated up to 12 hours prior to surgery in 288 hip replacement surgery patients who received enoxaparin peri-operatively in an unblinded fashion in one clinical trial.

2 Data represent enoxaparin 40 mg SC once a day given in a blinded fashion as extended prophylaxis at the end of the peri-operative period in 131 of the original 288 hip replacement surgery patients for up to 21 days in one clinical trial.

Table 10: Adverse Reactions Occurring at ≥2% Incidence in Enoxaparin-Treated Medical Patients with Severely Restricted Mobility During Acute Illness

 

Table 11: Adverse Reactions Occurring at ≥ 2% Incidence in Enoxaparin-Treated Patients Undergoing Treatment of Deep Vein Thrombosis with or without Pulmonary Embolism

Adverse Events in Enoxaparin-Treated Patients with Unstable Angina or Non-Q-Wave Myocardial Infarction:

Non-hemorrhagic clinical events reported to be related to enoxaparin therapy occurred at an incidence of ≤1%.

Non-major hemorrhagic events, primarily injection site ecchymoses and hematomas, were more frequently reported in patients treated with SC enoxaparin than in patients treated with IV heparin.

Serious adverse events with enoxaparin or heparin in a clinical trial in patients with unstable angina or non-Q-wave myocardial infarction that occurred at a rate of at least 0.5% in the enoxaparin group are provided below [see Table 12].

Table 12: Serious Adverse Events Occurring at ≥0.5% Incidence in Enoxaparin-Treated Patients with Unstable Angina or Non-Q-Wave Myocardial Infarction

Adverse Reactions in Enoxaparin-Treated Patients with Acute ST-Segment Elevation Myocardial Infarction:

In a clinical trial in patients with acute ST-segment elevation myocardial infarction, the only adverse reaction that occurred at a rate of at least 0.5% in the enoxaparin group was thrombocytopenia (1.5%).

8.2 Postmarketing Experience

There have been reports of epidural or spinal hematoma formation with concurrent use of enoxaparin and spinal/epidural anesthesia or spinal puncture. The majority of patients had a postoperative indwelling epidural catheter placed for analgesia or received additional drugs affecting hemostasis such as NSAIDs. Many of the epidural or spinal hematomas caused neurologic injury, including long-term or permanent paralysis.

Local reactions at the injection site (e.g. nodules, inflammation, oozing), systemic allergic reactions (e.g. pruritus, urticaria, anaphylactic/anaphylactoid reactions), vesiculobullous rash, rare cases of hypersensitivity cutaneous vasculitis, purpura, skin necrosis (occurring at either the injection site or distant from the injection site), thrombocytosis, and thrombocytopenia with thrombosis [see Warnings and Precautions] have been reported.

Cases of hyperkalemia have been reported. Most of these reports occurred in patients who also had conditions that tend toward the development of hyperkalemia (e.g., renal dysfunction, concomitant potassium-sparing drugs, administration of potassium, hematoma in body tissues). Very rare cases of hyperlipidemia have also been reported, with one case of hyperlipidemia, with marked hypertriglyceridemia, reported in a diabetic pregnant woman; causality has not been determined.

Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to estimate reliably their frequency or to establish a causal relationship to drug exposure.

9. OVERDOSAGE

Accidental overdosage following administration of enoxaparin may lead to hemorrhagic complications. Injected enoxaparin may be largely neutralized by the slow IV injection of protamine sulfate (1% solution). The dose of protamine sulfate should be equal to the dose of enoxaparin injected: 1 mg protamine sulfate should be administered to neutralize 1 mg enoxaparin, if enoxaparin sodium was administered in the previous 8 hours. An infusion of 0.5 mg protamine per 1 mg of enoxaparin sodium may be administered if enoxaparin sodium was administered greater than 8 hours previous to the protamine administration, or if it has been determined that a second dose of protamine is required. The second infusion of 0.5 mg protamine sulfate per 1 mg of enoxaparin may be administered if the aPTT measured 2 to 4 hours after the first infusion remains prolonged.

If at least 12 hours have elapsed since the last enoxaparin sodium injection, protamine administration may not be required; however, even with higher doses of protamine, the aPTT may remain more prolonged than following administration of heparin. In all cases, the anti-Factor Xa activity is never completely neutralized (maximum about 60%). Particular care should be taken to avoid overdosage with protamine sulfate. Administration of protamine sulfate can cause severe hypotensive and anaphylactoid reactions. Because fatal reactions, often resembling anaphylaxis, have been reported with protamine sulfate, it should be given only when resuscitation techniques and treatment of anaphylactic shock are readily available. For additional information consult the labeling of protamine sulfate injection products.

10. DRUG INTERACTIONS

Whenever possible, agents which may enhance the risk of hemorrhage should be discontinued prior to initiation of enoxaparin therapy. These agents include medications such as: anticoagulants, platelet inhibitors including acetylsalicylic acid, salicylates, NSAIDs (including ketorolac tromethamine), dipyridamole, or sulfinpyrazone. If co-administration is essential, conduct close clinical and laboratory monitoring [see Warnings and Precautions].

11. PHARMACOKINETICS

Absorption

Pharmacokinetic trials were conducted using the 100 mg/mL formulation. Maximum anti-Factor Xa and anti-thrombin (anti-Factor IIa) activities occur 3 to 5 hours after SC injection of enoxaparin. Mean peak anti-Factor Xa activity was 0.16 IU/mL (1.58 mcg/mL) and 0.38 IU/mL (3.83 mcg/mL) after the 20 mg and the 40 mg clinically tested SC doses, respectively. Mean (n = 46) peak anti-Factor Xa activity was 1.1 IU/mL at steady state in patients with unstable angina receiving 1 mg/kg SC every 12 hours for 14 days. Mean absolute bioavailability of enoxaparin, after 1.5 mg/kg given SC, based on anti-Factor Xa activity is approximately 100% in healthy subjects.

A 30 mg IV bolus immediately followed by a 1 mg/kg SC every 12 hours provided initial peak anti-Factor Xa levels of 1.16 IU/mL (n=16) and average exposure corresponding to 84% of steady-state levels. Steady state is achieved on the second day of treatment.

Enoxaparin pharmacokinetics appear to be linear over the recommended dosage ranges [see Dosage and Administration]. After repeated subcutaneous administration of 40 mg once daily and 1.5 mg/kg once-daily regimens in healthy volunteers, the steady state is reached on day 2 with an average exposure ratio about 15% higher than after a single dose. Steady-state enoxaparin activity levels are well predicted by single-dose pharmacokinetics. After repeated subcutaneous administration of the 1 mg/kg twice daily regimen, the steady state is reached from day 4 with mean exposure about 65% higher than after a single dose and mean peak and trough levels of about 1.2 and 0.52 IU/mL, respectively. Based on enoxaparin sodium pharmacokinetics, this difference in steady state is expected and within the therapeutic range.

Although not studied clinically, the 150 mg/mL concentration of enoxaparin sodium is projected to result in anticoagulant activities similar to those of 100 mg/mL and 200 mg/mL concentrations at the same enoxaparin dose. When a daily 1.5 mg/kg SC injection of enoxaparin sodium was given to 25 healthy male and female subjects using a 100 mg/mL or a 200 mg/mL concentration the following pharmacokinetic profiles were obtained [see Table 13].

Table 13: Pharmacokinetic Parameters* After 5 Days of 1.5 mg/kg SC Once Daily Doses of Enoxaparin Sodium Using 100 mg/mL or 200 mg/mL Concentrations

* Means ± SD at Day 5 and 90% Confidence Interval (CI) of the ratio

** Median (range)

Distribution

The volume of distribution of anti-Factor Xa activity is about 4.3 L.

Elimination

Following intravenous (IV) dosing, the total body clearance of enoxaparin is 26 mL/min. After IV dosing of enoxaparin labeled with the gamma-emitter, 99mTc, 40% of radioactivity and 8 to 20% of anti-Factor Xa activity were recovered in urine in 24 hours. Elimination half-life based on anti-Factor Xa activity was 4.5 hours after a single SC dose to about 7 hours after repeated dosing. Significant anti-Factor Xa activity persists in plasma for about 12 hours following a 40 mg SC once a day dose.

Following SC dosing, the apparent clearance (CL/F) of enoxaparin is approximately 15 mL/min.

Metabolism

Enoxaparin sodium is primarily metabolized in the liver by desulfation and/or depolymerization to lower molecular weight species with much reduced biological potency.

Renal clearance of active fragments represents about 10% of the administered dose and total renal excretion of active and non-active fragments 40% of the dose.

Special Populations

Gender: Apparent clearance and Amax derived from anti-Factor Xa values following single SC dosing (40 mg and 60 mg) were slightly higher in males than in females. The source of the gender difference in these parameters has not been conclusively identified; however, body weight may be a contributing factor.

Geriatric: Apparent clearance and Amax derived from anti-Factor Xa values following single and multiple SC dosing in geriatric subjects were close to those observed in young subjects. Following once a day SC dosing of 40 mg enoxaparin, the Day 10 mean area under anti-Factor Xa activity versus time curve (AUC) was approximately 15% greater than the mean Day 1 AUC value [see Dosage and Administration and Use in Specific Populations].

Renal Impairment: A linear relationship between anti-Factor Xa plasma clearance and creatinine clearance at steady state has been observed, which indicates decreased clearance of enoxaparin sodium in patients with reduced renal function. Anti-Factor Xa exposure represented by AUC, at steady state, is marginally increased in mild (creatinine clearance 50–80 mL/min) and moderate (creatinine clearance 30-50 mL/min) renal impairment after repeated subcutaneous 40 mg once-daily doses. In patients with severe renal impairment (creatinine clearance < 30 mL/min), the AUC at steady state is significantly increased on average by 65% after repeated subcutaneous 40 mg once-daily doses [see Dosage and Administration and Use in Specific Populations].

Hemodialysis: In a single study, elimination rate appeared similar but AUC was two-fold higher than control population, after a single 0.25 or 0.5 mg/kg intravenous dose.

Hepatic Impairment: Studies with enoxaparin in patients with hepatic impairment have not been conducted and the impact of hepatic impairment on the exposure to enoxaparin is unknown [see Use in Specific Populations (8.8)].

Weight: After repeated subcutaneous 1.5 mg/kg once daily dosing, mean AUC of anti-Factor Xa activity is marginally higher at steady state in obese healthy volunteers (BMI 30-48 kg/m2) compared to non-obese control subjects, while Amax is not increased.

When non-weight adjusted dosing was administered, it was found after a single-subcutaneous 40 mg dose, that anti-Factor Xa exposure is 52% higher in low-weight women (< 45 kg) and 27% higher in low-weight men (< 57 kg) when compared to normal weight control subjects [see Use in Specific Populations].

Pharmacokinetic interaction: No pharmacokinetic interaction was observed between enoxaparin and thrombolytics when administered concomitantly.

12. HOW SUPPLIED/STORAGE AND HANDLING

1) How Available:

a) Brand name: LOVENOX, by Sanofi-Aventis US.

b) International trade name: CLEXANE, by Sanofi-Aventis (France).

b) Generic drugs: Enoxaparin sodium, by Sandoz.

2) How Supplied:

Enoxaparin sodium injection, USP (by Sandoz) is available in two concentrations [see Tables 14 and 15]:

Table 14: 100 mg/mL Concentration

* Strength represents the number of milligrams of enoxaparin sodium in Water for Injection. Enoxaparin sodium injection, USP 30 and 40 mg prefilled syringes, and 60, 80, and 100 mg graduated prefilled syringes each contain 10 mg enoxaparin sodium per 0.1 mL Water for Injection.

† Approximate anti-Factor Xa activity based on reference to the W.H.O. Second International Low Molecular Weight Heparin Reference Standard.

‡ Each enoxaparin sodium injection, USP prefilled syringe is for single, one-time use only and is affixed with a 27 gauge × 1/2 inch needle.

Table 15: 150 mg/mL Concentration

* Strength represents the number of milligrams of enoxaparin sodium in Water for Injection. Enoxaparin sodium injection, USP 120 mg and 150 mg graduated prefilled syringes contain 15 mg enoxaparin sodium per 0.1 mL Water for Injection.

† Approximate anti-Factor Xa activity based on reference to the W.H.O. Second International Low Molecular Weight Heparin Reference Standard.

‡ Each enoxaparin sodium injection, USP graduated prefilled syringe is for single, one-time use only and is affixed with a 27 gauge × 1/2 inch needle.

3) Storage:

Store at 25°C (77F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature].

Do not store the multiple-dose vials for more than 28 days after the first use.

Keep out of the reach of children.

Rx only

Rev 04/11