[Effect of alclofenac on the prothrombin level in patients under treatment with anticoagulants]

Simultaneous administration of the anticoagulants acenocoumarol, phenprocoumon or chlorindion and the antirheumatic substance alclofenac in long term trials has no observable influence on the prothrombin time of stabilized patients. When the anticoagulant (acenocoumarol or phenprocoumon) and the alclofenac therapy are begun simultaneously, a variation of the dose is necessary. Either a one-third lower initial dosage can be given, or, after attaining the maximal anticoagulation effect on the prothrombin time (48 h after beginning acenocoumarol therapy, 72 h with phenprocoumarol), a lower daily dosage must be administered once, in comparison to the other group without alclofenac therapy. The maintenace dosage is not influenced by alclofenac.