Aspirin may substitute Warfarin for Deep Vein Clots

Aspirin  may substitute Warfarin for Deep Vein Clots

By Danisha .P

Asst Professor

Alshifa college of Pharmacy

Deep vein thrombosis (DVT) is a thrombus composed of  cellular materials bound together with fibrin strands. It is a manifestation of venous thromboembolism (VTE) which occurs due to clot formation in the venous circulation. Although a thrombus can form in any part of the venous circulation, the majority of the thrombi begin in the lower extremities. Once formed, a venous thrombus may remain asymptomatic, lyse spontaneously, obstruct the venous circulation, propogate into more proximal veins, embolize or act in combination in these ways. Symptoms of DVT include unilateral leg swelling, pain, tenderness, erythema and warmth. Since venous thrombi are mainly fibrin thrombi, anticoagulants are expected to be highly effective. Prophylaxis is recommended for all high risk patients including bedridden, old, post operative, post partum, post stroke and leg fracture patients. DVT can be life-threatening if clots break loose, travel to the lungs and block a pulmonary artery. When DVT has occurred, immediate heparin/warfarin therapy should be instituted. Three – six months warfarin therapy is also necessary. According to Australian researchers aspirin may offer an alternative for people who have had blood clots in the deep veins of the legs and cannot tolerate long-term use of blood thinners. Patients are usually prescribed blood thinners such as warfarin to prevent clot formation. Most people who have had a blood clot in a leg vein or an embolism where the clot blocks the blood flow have anticoagulant drug treatment, such as warfarin, for at least six months, first to dissolve the clot and then to prevent it happening again. However, long-term use of warfarin can be inconvenient, requiring frequent blood tests and dosage adjustments. Newer drugs, such as dabigatran and  rivaroxaban, are effective and do not require frequent blood tests. However, they are expensive, and some patients cannot tolerate them. Further, there is an elevated risk that the treatment can cause bleeding in some patients. Consequently, many patients choose not to continue such drugs after a period of time. Daily aspirin also reduces the risk of another clot without causing undue bleeding, compared with no treatment. The researchers have found that a daily aspirin reduced the risk of developing blood clots by 42 percent, compared with patients taking an inactive placebo during the trials. This is especially important for patients who are not able to take long-term anticoagulant medications for whatever reason, such as personal preference, adverse effects of the anticoagulant or cost. The treatment effect of aspirin is substantially smaller than what has been demonstrated with warfarin or the new oral blood thinners but in clinical trials with these drugs, an 80 to 90 percent reduction in clots has been demonstrated. For the study, the researchers analyzed the results of two trials that included 1,224 patients taking 100 milligrams of aspirin daily for at least two years and concluded that while less effective than other blood thinners, aspirin at least provides some protection, and in the case of the patients with DVT who don't have any other options, aspirin does provide benefit, which at the same time is a matter of argument.

References:

1. K D Tripathi. Essentials of medical pharmacology, sixth edition, page no:601-9.

2. Joseph T Dipiro et al, pharmacotherapy handbook, seventh edition, page no:171.

News courtesy: www.drugs.com/news