Could non steroidal anti-inflammatory drugs be used to potentiate L.M.W.H activity in thrombosis? (Part I).

Heparin fractions are antithrombotic drugs prescribed for preventive treatment but their efficacy must be optimized to permit curative use without side effects. The present study was performed on 144 rats receiving a low molecular weight heparin (L.M.W.H), Fraxiparine, and a non steroidal anti-inflammatory drug (Phenylbutazone), which were injected simultaneously or separately. Neither Phenylbutazone nor L.M.W.H at their lowest dose (1 mg/kg) reduced thrombus size. However, administered together, they produced a significant limitation of thrombus growth. Variation in anti Xa activity limitation was only observed with the highest dose of Fraxiparine alone or in combination with Phenylbutazone (1 mg/kg) corresponding to its antithrombotic effect.