PROLONGED THROMBOCYTOPENIA ASSOCIATED WITH PROCAINAMIDE IN AN ELDERLYPATIENT

OBJECTIVE: To report a case of thrombocytopenia associated with the us e of extended-release procainamide hydrochloride in a geriatric patien t. CASE SUMMARY: A 77-year-old man was admitted to the hospital for fo ur-vessel coronary artery bypass surgery. He subsequently developed ne w onset atrial fibrillation and was started on extended-release procai namide on hospital day 7. The patient's platelet count on admission wa s 229 x 10(9)/L. The platelet count began to decrease on hospital day 22 and was 79 x 10(9)/L by day 30 and 13 x 10(9)/L by hospital day 37. The patient exhibited gross hematuria and lower extremity petechiae. There were no signs of splenic sequestration and other hematologic ind ices were normal. Procainamide was discontinued on hospital day 32. Th ere was full recovery of the platelet count to baseline 33 days after procainamide was discontinued. DISCUSSION: Other possible medical and drug-related causes of thrombocytopenia are reviewed and ruled out. Pr evious reports of procainamide-associated thrombocytopenia describe an immune-mediated peripheral destruction of platelets with platelet rec overy within three to eight days after drug discontinuation. However, the prolonged recovery period and the presence of antiplatelet antibod ies suggest an immune-mediated process in the bone marrow of this pati ent. CONCLUSIONS: Clinicians should be aware of the possible adverse h ematologic effects of procainamide in die elderly.