What is known and objective: Neurotoxicity is a side effect of acyclovir. We report the first case, to our knowledge, whereby Bayesian-informed clearance estimates supported a therapeutic intervention for acyclovir-associated neurotoxicity.
Case summary: A 62-year-old male with the diagnosis of disseminated zoster was being treated with intravenous (IV) acyclovir when he developed symptoms of acute neurotoxicity. Acyclovir had been dose-adjusted for renal dysfunction according to traditional creatinine clearance estimates; however, as the patient was also on vancomycin, Bayesian estimates of vancomycin clearances were performed, which revealed a 2-fold lower creatinine clearance. In response to the Bayesian estimates, acyclovir was discontinued, and improvements in mentation were noted within 24 hours.
What is new and conclusion: Alternate approaches to estimate renal function beyond Cockcroft-Gault, such as a Bayesian approach used in our patient, should be considered when population estimates are likely to be inaccurate and potentially dangerous to the patient.
Keywords: acyclovir; adverse effects; pharmacodynamics; pharmacokinetics; statistical model.
© 2017 John Wiley & Sons Ltd.