[Inhibition of thrombocyte function by non-steroidal anti-rheumatic agents: a comparative study between diclofenac, acemetacin, mefenamic acid and ibuprofen].

Non-steroidal antiinflammatory drugs (NSAID) interfere with the synthesis of prostaglandins by inhibiting cyclooxygenase. In blood platelets, this leads to a lack of thromboxane synthesis comparable to the congenital defect which is known to be associated with enhanced bleeding tendency, although the bleeding time may not be prolonged. The four NSAID diclofenac, acemetacin, ibuprofen, and mefenamic acid administered to healthy volunteers at the recommended dosage led to significant suppression of thromboxane synthesis; this effect was more pronounced with acemetacin and ibuprofen than with diclofenac. After intake of NSAID enhanced bleeding during surgery must be expected; in individuals with additional impairment of the hemostatic system (i.e. treatment with oral anticoagulants, mild haemophilia, von Willebrand's disease, mild thrombocytopenia), spontaneous bleeding may occur.