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2022-12-09
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Pharmacy Practice & Practice-Based Research
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Copyright (c) 2022 Michael J. Schuh, Kevin Mustain, Sheena Crosby
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Copyright of content published in INNOVATIONS in pharmacy belongs to the author(s).
Phenytoin Toxicity with High Dose, Concomitant Ascorbic Acid Dosing
Michael J. Schuh
Mayo School of Health Related Sciences
Kevin Mustain
University of Florida College of Pharmacy
Sheena Crosby
Mayo Clinic Florida
DOI: https://doi.org/10.24926/iip.v13i4.5122
Keywords: phenytoin toxicity, vitamin C, ascorbic acid
Abstract
High dose ascorbic acid may increase risk of phenytoin toxicity. This case report demonstrates high phenytoin levels resulting in adverse drug reactions subsequent to dosing concomitantly with high dose vitamin C, or ascorbic acid (AA), as a precaution against acquiring corona virus (COVID) infection. This patient suffered from a major seizure when he ran out of his phenytoin prescription. Subsequent initiation of phenytoin and later addition of high dose AA resulted in truncal ataxia and falls with bilateral wrist and finger extension weakness. Phenytoin and AA were discontinued, and the patient returned to baseline on a new medication regimen of lacosamide and gabapentin without any other major seizures one year later.
