Low Molecular Weight Heparin (LMWH) & Fondaparinux - Quick points

LMWH

• They are used in the prevention of blood clots and treatment of DVT and PE and in the treatment of MI
• Heparin is a naturally occurring polysaccharide that inhibits coagulation, the process that leads to thrombosis.
• Natural heparin consists of molecular chains of varying lengths, or molecular weights.
• LMWHs consist of only short chains of polysaccharide, thus LMWHs have a lower molecular weight
• The effects of natural heparin are more unpredictable than LMWH
• eg Tinzaparin (highest molecular weight) , Enoxaparin, Dalteparin (lowest)
• Due to its renal clearance, LMWH is contraindicated in patients with kidney disease in whom unfractionated heparin can be used safely

Fondaparinux

• First in a new class of antithrombotic agents
• Inhibits thrombin generation by selectively inhibiting factor Xa
• Chemically synthesized; this leads to batch-to-batch consistency and the absence of potential risk of contamination problems. 
• Exhibits complete bioavailability by the subcutaneous route and is rapidly absorbed, reaching its maximum concentration approximately 2 h post dosing.
• It has a terminal half-life of 13 to 21 h, permitting once-daily dosing.
• Less individual dose adjustments, less monitoring, low potential for drug-drug interactions