ISSN: 0022-1198
CODEN: JFSCA
Page Count: 6

A Fatal Interaction of Methocarbamol and Ethanol in an Accidental Poisoning
Hagardorn, AN
Toxicologist and research specialist, Section of Toxicology, Department of Pharmacology, Quillen-Dishner College of Medicine, East Tennessee State University, TN

Ferslew, KE
Toxicologist and research specialist, Section of Toxicology, Department of Pharmacology, Quillen-Dishner College of Medicine, East Tennessee State University, TN

McCormick, WF
Deputy chief medical examiner of the State of Tennessee, Section of Forensic Pathology, Department of Pathology, Quillen-Dishner College of Medicine, East Tennessee State University, TN

(Received 10 February 1989; accepted 30 May 1989)

Abstract

A case is presented of a fatal drug interaction caused by ingestion of methocarbamol (Robaxin®) and ethanol. Methocarbamol is a carbamate derivative used as a muscle relaxant with sedative effects. Therapeutic concentrations of methocarbamol are reported to be 24 to 41 μg/mL. Biological fluids were screened for ethanol using the Abbott TDx system and quantitated by gas-liquid chromatography (GLC). Determination of methocarbamol concentrations in biological tissue homogenates and fluids were obtained by colorimetric analysis of diazotized methocarbamol. Blood ethanol concentration was 135 mg/dL (0.135% w/v) and urine ethanol was 249 mg/dL (0.249% w/v). Methocarbamol concentrations were: blood, 257 μg/mL; bile, 927 μg/mL; urine, 255 μg/mL; gastric, 3.7 g; liver, 459 μg/g; and kidney, 83 μg/g. The combination of ethanol and carbamates is contraindicated since acute alcohol intoxication combined with carbamate usage can lead to combined central nervous system depression as a result of the interactive sedative-hypnotic properties of the compounds.

Keywords:
toxicology, alcohol, methocarbamol, fatal drug interaction, ethanol

Paper ID: JFS12850J
DOI: 10.1520/JFS12850J
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