Treatment of Relapsed Plasmodium vivax with High-Dose Atovaquone–Proguanil in the Setting of Long-Term Rifampin Use

A 58-year-old man with a past medical history significant for cerebrovascular accident with residual quadriplegia and feeding-tube dependence, latent tuberculosis infection, and prior treated malaria who developed relapsed Plasmodium vivax infection while receiving rifampin-based therapy for latent tuberculosis is discussed. Although standard-dose atovaquone-proguanil remained a reasonable treatment option, an increased-dose regimen was selected given concern that rifampin-induced hepatic enzyme induction would lower atovaquone-proguanil plasma concentrations. The patient was treated with atovaquone-proguanil 2,000 mg/800 mg daily (double the standard dose of both components) for 6 days (double the standard 3-day duration) from hospital day 4 to hospital day 9. Primaquine 30 mg daily (standard dose) was started on hospital day 5 and continued for 14 days. This regimen achieved complete resolution of parasitemia and sustained clinical cure at follow-up.