Voriconazole-induced CNS Toxicity: A Case Study

Abstract

Voriconazole-induced central nervous system (CNS) toxicity is a common adverse drug reaction (ADR). It is associated with voriconazole plasma level higher than normal trough concentrations and other factors decreasing elimination of voriconazole. This CNS toxicity can be prevented by prescribing the recommended dose of voriconazole, on weight-based dosing. monitoring liver function test, and monitoring therapeutic drug level of voriconazole. Reduction or discontinuation of voriconazole could alleviate this ADR. In addition, the co-precipitating factor of voriconazole-induced CNS toxicity should be resolved. This is a case study of a 40-years old woman with B-cell acute lymphoblastic leukemia (B-ALL) developing confusion, disorganized speech symptoms, and hallucinations after three days of oral administration of voriconazole at 200 mg every 12 hours (4.7 mg/kg) for treatment of invasive pulmonary aspergillosis. Voriconazole-induced CNS toxicity was diagnosed and pharmacist was consulted. On reviewing the physical examination, the laboratory tests, and the medication history, there were evidences of a little bit higher blood level of voriconazole than recommended level and abnormal liver function test. These led to high blood level of voriconazole and induced CNS toxicity.
This report indicates the importance of preventing voriconazole-induced CNS toxicity. Pharmacist can play role in this prevention by screening high-risk patients, reviewing administered dose, and co-administered drugs, identifying drug interactions, consulting to monitor liver function test and therapeutic drug level, assessing for causes and co-precipitating factors leading to voriconazole-induced CNS toxicity.