Hypoprothrombinemia associated with cefamandole use in a rural teaching hospital.

The incidence of hypoprothrombinemia (prothrombin time greater than or equal to 2 s above the highest control) associated with concurrent cefamandole nafate usage in our institution was determined. Of 77 patients receiving cefamandole for no less than 48 hours, serial prothrombin time was monitored in 31 (40.2%). Four (12.9%) of 31 in whom a baseline normal prothrombin time was obtained developed hypoprothrombinemia during cefamandole therapy. An additional three patients for whom baseline prothrombin time was not determined were noted to have hypoprothrombinemia during therapy with cefamandole. Two patients had clinically significant bleeding episodes. The prothrombin time normalized in six of seven patients following administration of fresh frozen plasma, phytonadione therapy, discontinuation of cefamandole, or a combination of the three. This study illustrated that the incidence of hypoprothrombinemia associated with concurrent cefamandole use is relatively high. Serial prothrombin time monitoring is indicated when patients receive cefamandole.