Abdominal Surgery
The recommended dose of enoxaparin sodium injection is
40 mgby subcutaneous injection once a day (with the initial dose given 2 hours prior to surgery) in patients undergoing abdominal surgery who are at risk for thromboembolic complications. The usual duration of administration is 7 to 10 days
[see Clinical Studies (
14.1)]
.
Hip or Knee Replacement Surgery
The recommended dose of enoxaparin sodium injection is
30 mg every 12 hoursadministered by subcutaneous injection in patients undergoing hip or knee replacement surgery. Administer the initial dose 12 to 24 hours after surgery, provided that hemostasis has been established. The usual duration of administration is 7 to 10 days
[see Clinical Studies (
14.2)]
.
A dose of enoxaparin sodium injection of
40 mg once a daysubcutaneously may be considered for hip replacement surgery for up to 3 weeks. Administer the initial dose 12 (±3) hours prior to surgery.
Medical Patients During Acute Illness
The recommended dose of enoxaparin sodium injection is
40 mg once a dayadministered by subcutaneous injection for medical patients at risk for thromboembolic complications due to severely restricted mobility during acute illness. The usual duration of administration is 6 to 11 days
[see Clinical Studies (
14.3)]
.
Treatment of Deep Vein Thrombosis with or without Pulmonary Embolism
The recommended dose of enoxaparin sodium injection is
1 mg/kg every 12 hoursadministered subcutaneously in patients with acute deep vein thrombosis without pulmonary embolism, who can be treated at home in an outpatient setting.
The recommended dose of enoxaparin sodium injection is
1 mg/kg every 12 hoursadministered subcutaneously
or 1.5 mg/kg once a dayadministered subcutaneously at the same time every day for
inpatient (hospital) treatmentof 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).
In both outpatient and inpatient (hospital) treatments, initiate warfarin sodium therapy when appropriate (usually within 72 hours of enoxaparin sodium injection). Continue enoxaparin sodium injection for a minimum of 5 days and until a therapeutic oral anticoagulant effect has been achieved (International Normalization Ratio 2 to 3). The average duration of administration is 7 days
[see Clinical Studies (
14.4)]
.
Unstable Angina and Non-Q-Wave Myocardial Infarction
The recommended dose of enoxaparin sodium injection is
1 mg/kgadministered subcutaneously
every 12 hoursin conjunction with oral aspirin therapy (100 to 325 mg once daily) in patients with unstable angina or non-Q-wave myocardial infarction. Treat with enoxaparin sodium injection for a minimum of 2 days and continue until clinical stabilization. The usual duration of treatment is 2 to 8 days
[see Warnings and Precautions (
5.2) and Clinical Studies (
14.5)]
.
Treatment of Acute ST-Segment Elevation Myocardial Infarction
The recommended dose of enoxaparin sodium injection is a
single intravenous bolus of 30 mgplus a 1 mg/kg subcutaneous dose followed by 1 mg/kg administered subcutaneously every 12 hours (maximum 100 mg for the first two doses only, followed by 1 mg/kg dosing for the remaining doses) in patients with acute ST-segment elevation myocardial infarction. Reduce the dosage in patients ≥75 years of age
[see Dosage and Administration (
2.4)].
Unless contraindicated, administer aspirin to all patients as soon as they are identified as having STEMI and continue dosing with 75 to 325 mg once daily.
When administered in conjunction with a thrombolytic (fibrin specific or non–fibrin specific), administer enoxaparin sodium injection between 15 minutes before and 30 minutes after the start of fibrinolytic therapy. The usual duration of enoxaparin sodium injection therapy is 8 days or until hospital discharge.
For patients managed with percutaneous coronary intervention (PCI), if the last enoxaparin sodium injection subcutaneous administration was given less than 8 hours before balloon inflation, no additional dosing is needed. If the last enoxaparin sodium injection subcutaneous administration was given more than 8 hours before balloon inflation, administer an intravenous bolus of 0.3 mg/kg of enoxaparin sodium injection
[see Warnings and Precautions (
5.2)].
Intravenous (Bolus) Injection Technique
Use the multi-dose vial for intravenous injections. Administer enoxaparin sodium injection through an intravenous line. Do not mix or coadminister enoxaparin sodium injection with other medications. Flush the intravenous access device with a sufficient volume of saline or dextrose solution prior to and following the intravenous bolus administration of enoxaparin sodium injection, to prevent mixing of drugs. Enoxaparin sodium injection is compatible with normal saline solution (0.9%) or 5% dextrose in water.
Hemorrhage
The following rates of major bleeding events have been reported during clinical trials with enoxaparin sodium (see
Tables 2to
7).
Table 2: Major Bleeding Episodes following Abdominal and Colorectal Surgery*| * 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.
|
Indications
| Dosing Regimen |
Enoxaparin Sodium 40 mg daily subcutaneously
| Heparin 5,000 U q8h subcutaneously
|
Abdominal Surgery | n=555
23 (4%)
| n=560
16 (3%)
|
Colorectal Surgery | n=673
28 (4%)
| n=674
21 (3%)
|
Table 3: Major Bleeding Episodes following Hip or Knee Replacement Surgery*| * 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.
|
| †Enoxaparin sodium 30 mg every 12 hours subcutaneously initiated 12 to 24 hours after surgery and continued for up to 14 days after surgery
|
| ‡Enoxaparin sodium 40 mg subcutaneously once a day initiated up to 12 hours prior to surgery and continued for up to 7 days after surgery
|
| §Enoxaparin sodium 40 mg subcutaneously once a day for up to 21 days after discharge
|
Indications
| Dosing Regimen |
Enoxaparin Sodium 40 mg daily
subcutaneously
| Enoxaparin Sodium 30 mg q12h
subcutaneously
| Heparin 15,000 U/24h
subcutaneously
|
Hip Replacement Surgery without Extended Prophylaxis† | -- | n=786
31 (4%)
| n=541
32 (6%)
|
Hip Replacement Surgery with Extended Prophylaxis | -- | -- | -- |
Peri-operative Period
‡ | n=288
4 (2%)
| -- | -- |
Extended Prophylaxis Period
§ | n=221
0 (0%)
| -- | -- |
Knee Replacement Surgery without Extended Prophylaxis† | -- | n=294
3 (1%)
| n=225
3 (1%)
|
NOTE: At no time point were the 40 mg once a day pre-operative and the 30 mg every 12 hours postoperative 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 sodium patients versus 1.8% of the placebo patients.
Table 4: Major Bleeding Episodes in Medical Patients with Severely Restricted Mobility during Acute Illness*| * 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.
|
| †The rates represent major bleeding on study medication up to 24 hours after last dose.
|
Indication
| Dosing Regimen |
Enoxaparin Sodium† 20 mg daily subcutaneously
| Enoxaparin Sodium† 40 mg daily subcutaneously
| Placebo† |
Medical Patients during Acute Illness | n=351
1 (<1%)
| n=360
3 (<1%)
| n=362
2 (<1%)
|
Table 5: Major Bleeding Episodes in Deep Vein Thrombosis with or without Pulmonary Embolism Treatment*| * 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.
|
| †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 sodium or standard heparin therapy and continuing for up to 90 days.
|
Indication
| Dosing Regimen† |
Enoxaparin Sodium 1.5 mg/kg daily subcutaneously
| Enoxaparin Sodium 1 mg/kg q12h
subcutaneously
| Heparin aPTT Adjusted Intravenous Therapy
|
Treatment of DVT and PE | n=298
5 (2%)
| n=559
9 (2%)
| n=554
9 (2%)
|
Table 6: Major Bleeding Episodes in Unstable Angina and Non-Q-Wave Myocardial Infarction| * The rates represent major bleeding on study medication up to 12 hours after dose. |
| †Aspirin therapy was administered concurrently (100 to 325 mg per day).
|
| ‡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.
|
Indication
| Dosing Regimen |
Enoxaparin Sodium*
1 mg/kg q12h subcutaneously
| Heparin*
aPTT Adjusted Intravenous Therapy
|
Unstable Angina and Non-Q-Wave MI†,‡ | n=1578
17 (1%)
| n=1529
18 (1%)
|
Table 7: Major Bleeding Episodes in Acute ST-Segment Elevation Myocardial Infarction| * The rates represent major bleeding (including ICH) up to 30 days. |
| †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.
|
| Dosing Regimen |
Indication
| Enoxaparin Sodium*
Initial 30 mg intravenous bolus followed by
1 mg/kg q12h subcutaneously
| Heparin*
aPTT Adjusted
Intravenous Therapy
|
Acute ST-Segment Elevation Myocardial Infarction Major bleeding (including ICH)
† Intracranial hemorrhages (ICH)
| n=10176
n (%)
211 (
2.1)
84 (0.8)
| n=10151
n (%)
138 (
1.4)
66 (0.7)
|
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 sodium.
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 sodium should be interpreted with caution.
Local Reactions
Local irritation, pain, hematoma, ecchymosis, and erythema may follow subcutaneous injection of enoxaparin sodium.
Adverse Reactions in Patients Receiving Enoxaparin Sodium for Prophylaxis or Treatment of DVT, PE
Other adverse reactions that were thought to be possibly or probably related to treatment with enoxaparin sodium, 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 sodium group, are provided below (see
Tables 8to
11).
Table 8: Adverse Reactions Occurring at ≥2% Incidence in Enoxaparin Sodium-Treated Patients Undergoing Abdominal or Colorectal Surgery
Adverse Reaction
| Dosing Regimen |
Enoxaparin Sodium 40 mg daily subcutaneously
n=1228
%
| Heparin 5,000 U q8h subcutaneously
n=1234
%
|
Severe | Total | Severe | Total |
Hemorrhage | <1 | 7 | <1 | 6 |
Anemia | <1 | 3 | <1 | 3 |
Ecchymosis | 0 | 3 | 0 | 3 |
Table 9: Adverse Reactions Occurring at ≥2% Incidence in Enoxaparin Sodium-Treated Patients Undergoing Hip or Knee Replacement Surgery| * Data represent enoxaparin sodium 40 mg subcutaneously once a day initiated up to 12 hours prior to surgery in 288 hip replacement surgery patients who received enoxaparin sodium peri-operatively in an unblinded fashion in one clinical trial. |
| †Data represent enoxaparin sodium 40 mg subcutaneously 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.
|
Adverse Reaction
| Dosing Regimen |
Enoxaparin Sodium 40 mg daily
subcutaneously
| Enoxaparin Sodium 30 mg q12h
subcutaneously
| Heparin 15,000 U/24h
subcutaneously
| Placebo q12h
subcutaneously
|
Peri-operative
Period
| Extended
Prophylaxis
Period
| | | |
n=288*
%
| n=131
† %
| n=1080
%
| n=766
%
| n=115
%
|
Severe | Total | Severe | Total | Severe | Total | Severe | Total | Severe | Total |
Fever | 0 | 8 | 0 | 0 | <1 | 5 | <1 | 4 | 0 | 3 |
Hemorrhage | <1 | 13 | 0 | 5 | <1 | 4 | 1 | 4 | 0 | 3 |
Nausea | -- | -- | -- | | <1 | 3 | <1 | 2 | 0 | 2 |
Anemia | 0 | 16 | 0 | <2 | <1 | 2 | 2 | 5 | <1 | 7 |
Edema | -- | -- | -- | -- | <1 | 2 | <1 | 2 | 0 | 2 |
Peripheral edema | 0
| 6
| 0
| 0
| <1
| 3
| <1
| 4
| 0
| 3
|
Table 10: Adverse Reactions Occurring at ≥2% Incidence in Enoxaparin Sodium-Treated Medical Patients with Severely Restricted Mobility during Acute Illness
Adverse Reaction
| Dosing Regimen |
Enoxaparin Sodium 40 mg daily subcutaneously
n=360
%
| Placebo daily subcutaneously
n=362
%
|
Dyspnea | 3.3 | 5.2 |
Thrombocytopenia | 2.8 | 2.8 |
Confusion | 2.2 | 1.1 |
Diarrhea | 2.2 | 1.7 |
Nausea | 2.5 | 1.7 |
Table 11: Adverse Reactions Occurring at ≥2% Incidence in Enoxaparin Sodium-Treated Patients Undergoing Treatment of Deep Vein Thrombosis with or without Pulmonary Embolism
Adverse Reaction
| Dosing Regimen |
Enoxaparin Sodium 1.5 mg/kg daily
subcutaneously
n=298
| Enoxaparin Sodium 1 mg/kg q12h
subcutaneously
n=559
| Heparin aPTT Adjusted Intravenous
Therapy
n=544
|
% | % | % |
Severe | Total | Severe | Total | Severe | Total |
Injection Site Hemorrhage | 0 | 5 | 0 | 3 | <1 | <1 |
Injection Site Pain | 0 | 2 | 0 | 2 | 0 | 0 |
Hematuria | 0 | 2 | 0 | <1 | <1 | 2 |
Adverse Events in Enoxaparin Sodium-Treated Patients with Unstable Angina or Non-Q-Wave Myocardial Infarction
Non-hemorrhagic clinical events reported to be related to enoxaparin sodium therapy occurred at an incidence of ≤1%.
Non-major hemorrhagic events, primarily injection site ecchymosis and hematomas, were more frequently reported in patients treated with subcutaneous enoxaparin sodium than in patients treated with intravenous heparin.
Serious adverse events with enoxaparin sodium 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 sodium group are provided below (see
Table 12).
Table 12: Serious Adverse Events Occurring at ≥0.5% Incidence in Enoxaparin Sodium-Treated Patients with Unstable Angina or Non-Q-Wave Myocardial Infarction
Adverse Event
| Dosing Regimen |
Enoxaparin Sodium 1 mg/kg q12h subcutaneously
n=1578
n (%)
| Heparin aPTT Adjusted
Intravenous Therapy
n=1529
n (%)
|
Atrial fibrillation | 11 (0.70) | 3 (0.20) |
Heart failure | 15 (0.95) | 11 (0.72) |
Lung edema | 11 (0.70) | 11 (0.72) |
Pneumonia | 13 (0.82) | 9 (0.59) |
Adverse Reactions in Enoxaparin Sodium-Treated Patients with Acute ST-Segment Elevation Myocardial Infarction
In a clinical trial in patients with acute ST-segment elevation myocardial infarction, thrombocytopenia occurred at a rate of 1.5%.
Risk Summary
Placental transfer of enoxaparin was observed in the animal studies. Human data from a retrospective cohort study, which included 693 live births, suggest that enoxaparin does not increase the risk of major developmental abnormalities
(see
Data)
. Based on animal data, enoxaparin sodium is not predicted to increase the risk of major developmental abnormalities
(see
Data)
.
Adverse outcomes in pregnancy occur regardless of the health of the mother or the use of medications. The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
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 (
5.7) and Use in Specific Populations (
8.6)]
. 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 sodium 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 sodium 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 sodium 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 multi-dose vial of enoxaparin sodium contains 15 mg benzyl alcohol per 1 mL as a preservative
[see Warnings and Precautions (
5.8)]
.
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 sodium 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 sodium. 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 sodium in pregnant women with mechanical prosthetic heart valves has been conducted
[see Warnings and Precautions (
5.7)]
.
Animal Data
Teratology studies have been conducted in pregnant rats and rabbits at subcutaneous doses of enoxaparin up to 15 times the recommended human dose (by comparison with 2 mg/kg as the maximum recommended daily dose). There was no evidence of teratogenic effects or fetotoxicity due to enoxaparin. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Risk Summary
It is unknown whether enoxaparin sodium is excreted in human milk. In lactating rats, the passage of enoxaparin or its metabolites in the milk is very limited. There is no information available on the effect of enoxaparin or its metabolites on the breastfed child, or on the milk production. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for enoxaparin sodium and any potential adverse effects on the breastfed child from enoxaparin sodium or from the underlying maternal condition.
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 sodium in clinical trials. The efficacy of enoxaparin sodium 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 sodium were employed. The incidence of bleeding complications was higher in geriatric patients as compared to younger patients when enoxaparin sodium was administered at doses of 1.5 mg/kg once a day or 1 mg/kg every 12 hours. The risk of enoxaparin sodium-associated bleeding increased with age. Serious adverse events increased with age for patients receiving enoxaparin sodium. Other clinical experience (including postmarketing surveillance and literature reports) has not revealed additional differences in the safety of enoxaparin sodium between geriatric and younger patients. Careful attention to dosing intervals and concomitant medications (especially antiplatelet medications) is advised. Enoxaparin sodium 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 (
2.6) and Clinical Pharmacology (
12.3)]
.
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 intravenous bolus prior to the normal dosage regimen and had their subcutaneous dose adjusted to 0.75 mg/kg every 12 hours
[see Dosage and Administration (
2.4)]
. The incidence of bleeding complications was higher in patients ≥65 years of age as compared to younger patients (<65 years).
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 subcutaneous 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 subcutaneous 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 subcutaneously every 12 hours for 14 days. Mean absolute bioavailability of enoxaparin, after 1.5 mg/kg given subcutaneously, based on anti-Factor Xa activity is approximately 100% in healthy subjects.
A 30 mg intravenous bolus immediately followed by 1 mg/kg subcutaneously 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 appears to be linear over the recommended dosage ranges
[see Dosage and Administration (
2)]
. 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 subcutaneous 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 Subcutaneous 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)
|
| Concentration | Anti-Xa | Anti-IIa | Heptest | aPTT |
A
max (IU/mL or Δ sec)
| 100 mg/mL
| 1.37 (±0.23)
| 0.23 (±0.05)
| 105 (±17)
| 19 (±5)
|
200 mg/mL | 1.45 (±0.22) | 0.26 (±0.05) | 111 (±17) | 22 (±7) |
90% CI | 102%-110% | | 102%-111% | |
t
max†(h)
| 100 mg/mL | 3 (2-6) | 4 (2-5) | 2.5 (2-4.5) | 3 (2-4.5) |
200 mg/mL | 3.5 (2-6) | 4.5 (2.5-6) | 3.3 (2-5) | 3 (2-5) |
AUC(ss)
(h*IU/mL or h* Δ sec)
| 100 mg/mL
| 14.26 (±2.93)
| 1.54 (±0.61)
| 1321 (±219)
| |
200 mg/mL | 15.43 (±2.96) | 1.77 (±0.67) | 1401 (±227) |
90% CI | 105%-112% | | 103%-109% |
Distribution
The volume of distribution of anti-Factor Xa activity is about 4.3 L.
Elimination
Following intravenous dosing, the total body clearance of enoxaparin is 26 mL/min. After intravenous 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 subcutaneous dose to about 7 hours after repeated dosing. Significant anti-Factor Xa activity persists in plasma for about 12 hours following a 40 mg subcutaneous once a day dose.
Following subcutaneous 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 A
maxderived from anti-Factor Xa values following single subcutaneous 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 A
maxderived from anti-Factor Xa values following single and multiple subcutaneous dosing in geriatric subjects were close to those observed in young subjects.
Following once a day subcutaneous 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 (
2.4) and Use in Specific Populations (
8.5)]
.
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 patients with creatinine clearance 50 to 80 mL/min and patients with creatinine clearance 30 to <50 mL/min 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 (
2.3) and Use in Specific Populations (
8.7)]
.
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 sodium in patients with hepatic impairment have not been conducted and the impact of hepatic impairment on the exposure to enoxaparin is unknown.
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/m
2) compared to non-obese control subjects, while A
maxis 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 (
8.8)]
.
Pharmacokinetic Interaction
No pharmacokinetic interaction was observed between enoxaparin sodium and thrombolytics when administered concomitantly.
Extended Prophylaxis of Deep Vein Thrombosis following Hip Replacement Surgery
In a study of extended prophylaxis for patients undergoing hip replacement surgery, patients were treated, while hospitalized, with enoxaparin sodium 40 mg subcutaneously, initiated up to 12 hours prior to surgery for the prophylaxis of postoperative DVT. At the end of the peri-operative period, all patients underwent bilateral venography. In a double-blind design, those patients with no venous thromboembolic disease were randomized to a post-discharge regimen of either enoxaparin sodium 40 mg (n=90) once a day subcutaneously or to placebo (n=89) for 3 weeks. A total of 179 patients were randomized in the double-blind phase of the study and all patients were treated. Patients ranged in age from 47 to 87 years (mean age 69.4 years) with 57% men and 43% women. In this population of patients, the incidence of DVT during extended prophylaxis was significantly lower for enoxaparin sodium compared to placebo. The efficacy data are provided below (see
Table 19).
Table 19: Efficacy of Enoxaparin Sodium in the Extended Prophylaxis of Deep Vein Thrombosis following Hip Replacement Surgery| * p value versus placebo = 0.008 |
| †CI= Confidence Interval
|
| ‡p value versus placebo = 0.537
|
Indication (Post Discharge)
| Post-discharge Dosing Regimen |
Enoxaparin Sodium 40 mg daily
subcutaneously
n (%)
| Placebo daily
subcutaneously
n (%)
|
All Treated Extended Prophylaxis Patients | 90 (100) | 89 (100) |
Treatment Failures
Total DVT (%)
| 6 (7)*
(95% CI
†: 3 to 14)
| 18 (20)
(95% CI: 12 to 30)
|
Proximal DVT (%) | 5 (6)
‡ (95% CI: 2 to 13)
| 7 (8)
(95% CI: 3 to 16)
|
In a second study, patients undergoing hip replacement surgery were treated, while hospitalized, with enoxaparin sodium 40 mg subcutaneously, initiated up to 12 hours prior to surgery. All patients were examined for clinical signs and symptoms of venous thromboembolic (VTE) disease. In a double-blind design, patients without clinical signs and symptoms of VTE disease were randomized to a post-discharge regimen of either enoxaparin sodium 40 mg (n=131) once a day subcutaneously or to placebo (n=131) for 3 weeks. A total of 262 patients were randomized in the study double-blind phase and all patients were treated. Patients ranged in age from 44 to 87 years (mean age 68.5 years) with 43.1% men and 56.9% women. Similar to the first study the incidence of DVT during extended prophylaxis was significantly lower for enoxaparin sodium compared to placebo, with a statistically significant difference in both total DVT (enoxaparin sodium 21 [16%] versus placebo 45 [34%]; p=0.001) and proximal DVT (enoxaparin sodium 8 [6%] versus placebo 28 [21%]; p=<0.001).