Voriconazole-induced Severe Hyperkalemia Precipitated by Multiple Drug Interactions

Voriconazole, a triazole antifungal agent used to treat serious fungal infections, has a pharmacokinetic characteristic of undergoing hepatic metabolism by the cytochrome P450 system. Few cases of hyperkalemia have been reported, which presented only when the serum voriconazole level was exceptionally elevated by drug-drug interactions. Additionally, azole antifungals may interfere with the biosynthesis of adrenal steroids and therefore can predispose patients to aldosterone deficiency. However, it is unclear whether voriconazole itself can induce hypoaldosteronism or hyperkalemia. Here, we report a case of voriconazole-induced hyperkalemia in a patient administered concurrent medications to treat comorbidities. Voriconazole was orally administered for pulmonary aspergillosis, and three episodes of severe hyperkalemia recurred, which improved with emergency treatment. In the first episode, renin-angiotensin-aldosterone system inhibitors were associated. We found that dronedarone might have increased the voriconazole level in the second episode. At that time, severe hypercalcemia was concurrent, which improved with acute hemodialysis and eliminating dronedarone. Finally, severe hyperkalemia recurred without concurrent medications known to interact with voriconazole. Upon switching from voriconazole to itraconazole, the hyperkalemia was resolved. Drug level monitoring is necessary when voriconazole is used. Genetic susceptibility, such as through CYP2C19 polymorphism, may be investigated for patients with adverse reactions to voriconazole.