Elsevier

Annals of Emergency Medicine

Late Increase in Acetaminophen Concentration After Overdose of Tylenol Extended Relief☆,☆☆,★

Presented at the North American Congress of Clinical Toxicology, Rochester, New York, September 1995.

Abstract

We report a case demonstrating a late increase in acetaminophen concentration after ingestion of Tylenol Extended Relief (extended-release acetaminophen; McNeil Consumer Products) along with drugs known to slow gastrointestinal motility. Coingestants that slow gastrointestinal motility are known to affect the interpretation of serum drug concentrations. However, this case illustrates potentially significant differences between extended-release and immediate-release acetaminophen and demonstrates an exception to the current manufacturer recommendation for the use of the Rumack-Matthew nomogram in this setting. [Bizovi KE, Aks SE, Paloucek F, Gross R, Keys N, Rivas J: Late increase in acetaminophen concentration after overdose of Tylenol Extended Relief. Ann Emerg Med November 1996;28: 549-551.]

Section snippets

INTRODUCTION

Although the management of standard-formulation acetaminophen exposure is well established,1, 2, 3 data regarding Tylenol Extended Relief (extended-release acetaminophen; McNeil Consumer Products) in the overdose setting are scarce. The manufacturer suggests measuring the concentration 4 hours after ingestion and again 4 to 6 hours after the first determination.4 In this report we describe a late increase in acetaminophen concentration after ingestion of extended release acetaminophen along

CASE REPORT

A 25-year-old woman presented to the emergency department about 1.5 hours after ingesting Tylenol Extended Relief and liquid Nyquil. She estimated ingesting more than half the 100-count bottle of extended-release acetaminophen and 8 ounces of Nyquil. The patient was suicidal and denied any other ingestions. Her prescribed medications were paroxetine 50 mg at bedtime, synthroid .075 once a day, thioridazine 50 mg at bedtime, one clonidine patch each week, omeprazole 20 mg once a day, and Bactrim

DISCUSSION

The unique feature of this case is the late increase in acetaminophen concentration 14 hours after the ingestion of the new product Tylenol Extended Relief (extended-release acetaminophen). The 6- and 10-hour postingestion concentrations we measured are nontoxic according to the Rumack-Matthew nomogram, but the subsequent three concentrations are all in the "potential for toxicity" range.1

Current manufacturer's recommendation for the management of extended-release acetaminophen overdose is to

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