Case Report

Grapefruit Juice and Verapamil: A Toxic Cocktail

Authors: Unnikrishnan Pillai MD, Jameel Muzaffar MD, Sandeep Sen MD, Abigail Yancey PharmD, BCPS

Abstract

Abstract:The US public consumes grapefruit juice in large quantities, with 14% of the population drinking the juice at least weekly. Grapefruit juice is a well-documented inhibitor of the CYP3A4 isoenzyme, which is involved in the metabolism of over 50% of commonly prescribed drugs. Here we report an unusual case of verapamil toxicity in a 42-year-old female, which resulted from accidental ingestion of only three tablets of the sustained release preparation (120 mg each) over 24 hours which resulted in severe toxicity.

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References

References1. Bailey DG, Dresser GK. Natural products and adverse drug interactions. CMAJ 2004;170:1531–1532.BaileyDG]]DresserGKNatural products and adverse drug interactions.CMAJ20041701531-15322. McAllister RG Jr. Clinical pharmacology of slow channel blocking agents. Prog Cardiovasc Dis 1982;25:83–102.McAllisterRGJrClinical pharmacology of slow channel blocking agents.Prog Cardiovasc Dis19822583-1023. Flanagan D. Understanding the grapefruit-drug interaction. Gen Den 2005;53:282–285.FlanaganDUnderstanding the grapefruit-drug interaction.Gen Den200553282-2854. Zaidenstein R, Dishi V, Gips M, et al. The effect of grapefruit juice on the pharmacokinetics of orally administered verapamil. Eur J Clin Pharmacol 1998;54:337–340.ZaidensteinR]]DishiV]]GipsM&etal;The effect of grapefruit juice on the pharmacokinetics of orally administered verapamil.Eur J Clin Pharmacol199854337-3405. Calan (Verapamil) Package Insert. New York, Pfizer, 2006.