Pentoxifylline-Induced Thrombocytopenia

Abstract

Pentoxifylline-induced thrombocytopenia is rare, and information is lacking about its presentation. We describe a 72-year-old Chinese male who developed thrombocytopenia after initiation of pentoxifylline for the treatment of chronic lower limb ischemia due to peripheral artery disease. Venous thromboembolism had been ruled out with an ultrasound. Vascular surgeons had also determined there was no indication for surgical intervention. Four days after initiation of pentoxifylline, he developed thrombocytopenia, and his platelets were 68 × 103/μL. He was not in overt disseminated intravascular coagulation (DIC), based on his International Society for Thrombosis and Hemostasis (ISTH) DIC score of 4. Dengue fever, which is endemic in Singapore, was ruled out. Pseudothrombocytopenia was also excluded with a peripheral blood film. When his platelets continued to fall, pentoxifylline was discontinued on the fifth day of treatment, and platelets normalized 48 hours after discontinuation. Pentoxifylline was a probable cause of thrombocytopenia using the Naranjo Adverse Drug Reaction Probability Scale (score = 7). The patient did not receive further doses of pentoxifylline. Prescribers should be aware of the risk of thrombocytopenia with pentoxifylline therapy and discontinue its use promptly if it is suspected.