The Hemostatic Defect Produced by Carbenicillin

Abstract

Blood coagulation and platelet function were examined in 17 human volunteers receiving doses of 300, 400 or 600 mg per kilogram per day of carbenicillin. Platelet function was also investigated in five patients receiving carbenicillin for the treatment of gram-negative infection. In volunteers, plasma coagulation remained normal. However, defective platelet function was seen in all volunteers and patients. Eleven of 11 volunteers demonstrated abnormal adenosine-diphosphate-induced platelet aggregation; six of 11 demonstrated abnormal l-epinephrine-induced aggregation, and five of 11 abnormal collagen-induced aggregation; in 14 of 20 studies, there was prolongation of bleeding time; seven of 11 volunteers had reduced clot retraction; eight of 11 had decreased prothrombin consumption. Prolongation of bleeding time and defective clot retraction appeared to be dose dependent. Three volunteers given 600 mg per kilogram per day and two patients given 340 and 375 mg per kilogram per day, respectively, experienced bleeding while receiving carbenicillin. The mechanism of platelet inhibition by carbenicillin is unknown. (N Engl J Med 291:265–270, 1974)