Severe Hyperkalemia Complicating Voriconazole Treatment in a Kidney Transplant Recipient With Histoplasmosis: A Case Report.

Voriconazole is an antifungal agent that is commonly used in immunocompromised patients who develop fungal infections. We report a case of severe recurrent hyperkalemia that developed after starting voriconazole for the treatment of histoplasmosis in a kidney transplant patient who was maintained on tacrolimus-based immunosuppression. Hyperkalemia developed despite reducing the tacrolimus dose to maintain levels in a low therapeutic range. Although interactions between azoles and calcineurin inhibitors are widely recognized, this is the 1st report describing new-onset hyperkalemia following initiation of voriconazole in a kidney transplant patient receiving tacrolimus.