Bemiparin

Bemiparin is a low molecular weight heparin (LMWH) used as an anticoagulant for the prevention and treatment of thromboembolic disorders. It is marketed under the trade names Ivor and Zibor.

Pharmacology

Bemiparin is a second-generation LMWH derived from porcine heparin through controlled depolymerization. It has a mean molecular weight of approximately 3,600 Daltons. The anticoagulant activity of bemiparin is primarily due to its ability to inhibit factor Xa, with a lesser effect on thrombin (factor IIa).

Mechanism of Action

Bemiparin exerts its anticoagulant effect by binding to antithrombin III (ATIII), which enhances the inhibition of factor Xa. This inhibition prevents the conversion of prothrombin to thrombin, thereby reducing the formation of fibrin clots. Unlike unfractionated heparin, bemiparin has a higher ratio of anti-factor Xa to anti-factor IIa activity, which contributes to its efficacy and safety profile.

Pharmacokinetics

Bemiparin is administered via subcutaneous injection. It has a rapid onset of action, with peak plasma levels occurring approximately 2 to 3 hours post-injection. The elimination half-life of bemiparin is about 5 to 6 hours, allowing for once-daily dosing in most therapeutic regimens. It is primarily eliminated through the renal system.

Clinical Uses

Bemiparin is indicated for several clinical applications:

• Prophylaxis of Venous Thromboembolism (VTE): Bemiparin is used to prevent VTE in patients undergoing orthopedic surgery, such as hip replacement or knee replacement, and in patients with restricted mobility due to acute medical illness.

• Treatment of Deep Vein Thrombosis (DVT): It is used in the treatment of acute DVT, with or without pulmonary embolism (PE).

• Prevention of Thromboembolic Complications in Hemodialysis: Bemiparin is used to prevent clot formation in the extracorporeal circuit during hemodialysis.

Adverse Effects

Common adverse effects of bemiparin include:

• Bleeding: As with other anticoagulants, the primary risk associated with bemiparin is bleeding. This can range from minor bruising to major hemorrhagic events.

• Thrombocytopenia: Although less common than with unfractionated heparin, bemiparin can cause heparin-induced thrombocytopenia (HIT).

• Injection Site Reactions: Patients may experience pain, redness, or swelling at the injection site.

Contraindications

Bemiparin is contraindicated in patients with:

• Active major bleeding
• Severe thrombocytopenia
• History of HIT
• Hypersensitivity to bemiparin or any of its components

Monitoring

Routine monitoring of coagulation parameters is generally not required with bemiparin due to its predictable pharmacokinetic profile. However, monitoring may be necessary in certain populations, such as patients with renal impairment or those at high risk of bleeding.

Special Populations

Renal Impairment

In patients with renal impairment, the clearance of bemiparin may be reduced, necessitating dose adjustments and careful monitoring for signs of bleeding.

Pregnancy and Lactation

Bemiparin is classified as a Category B drug for use in pregnancy, indicating that there is no evidence of harm to the fetus in animal studies, but adequate and well-controlled studies in pregnant women are lacking. It should be used during pregnancy only if clearly needed.

See Also

• Heparin
• Anticoagulant
• Thromboembolism