SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

P7
A COMBINED DRUG INTOXICATION INVOLVING METAXALONE (SKELAXIN®)
Juraj Cervenak*, Sarah M. Colvin, and Fiona J. Couper
Office of the Chief Medical Examiner, 1910 Massachusetts Ave SE, Bldg 27, Washington, D.C. 20003.
We present a case of a 24-year old female who was found dead on her bedroom floor, in a secure
apartment. She had a history of anxiety and had been prescribed antidepressants for several years. A scene
investigation revealed empty beer cans and numerous prescription and over-the-counter medications.
Prescribed medications included Lexapro® (citalopram), Skelaxin® (metaxalone), Ritalin®
(methylphenidate), and Restoril® (temazepam). An autopsy was performed and the findings were
unremarkable. Specimens were submitted for a full toxicological analysis, including an alcohol analysis by
headspace gas chromatography with flame ionization detection; a screen for drugs of abuse and several
prescription drug classes using an enzyme-linked immunosorbent assay technique (ELISA); and a screen
for basic compounds using gas chromatography-mass spectrometry (GC-MS). Positive findings were
confirmed and quantitated using GC-MS. The following drug concentrations were measured in postmortem
blood: metaxalone 38 mg/L, citalopram 0.49 mglL, diphenhydramine 0.10 mgIL and ethanol 0.02 g/100
mL. Methylphenidate and temazepam were not detected. Further investigation revealed the following
prescription history for the decedent prior to her death:
# Prescribed # Remainin
100 tablets 66 tablets
180 o
60 o
30 5
Metaxalone is a centrally acting muscle relaxant prescribed for the relief of pain associated with acute,
musculoskeletal conditions. The recommended dose for adults is 2 x 400 mg tablets, three to four times a
day. The circumstances and drug results in this case were similar to those reported in the only other
metaxalone-related fatality cited in the literature: a 29-year old female with a history of depression had
postmortem blood metaxalone and citalopramconcentrations of 39 mglL and 0.77 mgIL, respectively. In
the present study, the cause of death was determined to be due to "combined effects of metaxaione,
citaiopram, diphenhydramine and ethanof', and the manner of death was "undeterminec!'. A discussion of
the case circumstances, the toxicology findings and the pharmacology of metaxalone will be presented.
Keywords: Metaxalone, Skelaxin, Intoxication
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