Methemoglobinemia Secondary to Primaquine Therapy in an HIV Patient with Pneumocystis carinii Pneumonia—A Case Report

Abstract

Purpose: To describe an adverse drug event in a human immunodeficiency virus (HIV) patient treated with primaquine for Pneumocystis carinii (PCP) pneumonia. Summary: A 29-year-old black male presented to the outpatient clinic with symptoms of shortness of breath, nausea, and stomach cramps. The patient had received 10 days of primaquine 15 mg po q d and clindamycin 450 mg po qid for active PCP infection. The patient was found to have a methemoglobin level of 3%. The patient was diagnosed with primaquine-induced methemoglobinemia and admitted to the hospital. He was treated with methylene blue 120 mg IV, prednisone 40 mg po bid (tapered), ascorbic acid 500 mg po q d, and pentamidine 200 mg IV q 24 hrs. During the hospital course, the patient stabilized and was discharged upon completion of his pentamidine therapy. Conclusions: Reporting adverse drug events with all HIV-related therapies is key to enhancing the awareness and possibly preventing future adverse events.