Enoxaparin Dosage Adjustment Needed in Renal Impairment
Patients with severe renal impairment should receive less enoxaparin than other patients, according to a company letter that the Food and Drug Administration circulated Tuesday.
The instruction, contained in a March 2004 letter from Aventis Pharmaceuticals Inc. and the new labeling for Lovenex, noted that patients with a creatinine clearance less than 30 mL/min had a higher-than-normal exposure to enoxaparin, a drug that interferes with the process of blood coagulation.
According to the product's labeling, which now includes more information about the pharmacokinetics of enoxaparin, a regimen of once-daily 40-mg doses to patients with severe renal impairment resulted in a 65-percent higher exposure than occurred with a group of patients with better kidney function. No information was provided on what effect, if any, this "significantly increased" exposure had on the patients.
The new dosage regimens recommended for patients with severe renal impairment appear in Lovenox's labeling and are as follows:
- Prophylaxis in abdominal or hip- or knee-replacement surgery, 30 mg by subcutaneous (s.c.) injection once daily,
- Prophylaxis in medical patients with severely restricted mobility during an acute illness, 30 mg by s.c. injection once daily,
- Prophylaxis of the ischemic complications of unstable angina and non-Q-wave myocardial infarction, 1 mg/kg by s.c. injection once daily plus aspirin therapy,
- Inpatient treatment of acute deep venous thrombosis, 1 mg/kg by s.c. injection once daily plus warfarin therapy, and
- Outpatient treatment of acute deep vein thrombosis without pulmonary embolism, 1 mg/kg by s.c. injection once daily plus warfarin therapy.
Low-weight men and women also were found to have a higher-than-normal exposure to the drug, but this was less than was found for the patients with severe renal impairment and no change in dosage was specifically recommended.
Fondaparinux, another drug that interferes with the blood coagulation cascade, is unusable in patients with severe renal impairment and for prophylactic therapy in patients weighing less than 50 kg and undergoing hip-fracture or hip- or knee-replacement surgery.