Brief ReportsDetection of the Novel Metabolite Ethylphenidate After Methylphenidate Overdose With Alcohol CoingestionMarkowitz, John S. PharmD; Logan, Barry K. PhD, DABFT; Diamond, Fran BS; Patrick, Kennerly S. PhD, FCP Author Information (Markowitz, Patrick) Department of Pharmaceutical Sciences, Medical University of South Carolina, Charleston, South Carolina; (Logan) Department of Laboratory Medicine, University of Washington, Seattle, Washington; (Diamond) National Medical Services Inc., Willow Grove, Pennsylvania Received March 8, 1999; accepted after revision April 28, 1999. Address requests for reprints to: John S. Markowitz, PharmD, Institute of Psychiatry, Room 338N, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29425. Journal of Clinical Psychopharmacology: August 1999 - Volume 19 - Issue 4 - p 362-366 Buy Abstract Methylphenidate is the most commonly prescribed psychostimulant in clinical use today.Known methylphenidate metabolites include ritalinic acid, corresponding lactams, and p-hydroxymethylphenidate. Recent in vitro work using rat liver preparations has indicated that the methylphenidate ethyl ester, ethylphenidate, is formed upon incubation with ethanol. This report describes the first detection of ethylphenidate in human blood and liver samples obtained from two suicide victims who had overdosed on methylphenidate and coingested ethanol. Amounts of ethylphenidate detected in whole blood specimens in these two cases (8 ng/mL and 1 ng/mL, respectively) were small relative to methylphenidate and ritalinic acid concentrations. Nonetheless, given the high likelihood that methylphenidate and ethanol coingestion frequently occurs, the detection of ethylphenidate in humans warrants further investigation into the extent of its formation as well as into any associated toxicity in nonoverdose situations. (J Clin Psychopharmacol 1999;19:362-366) © 1999 Lippincott Williams & Wilkins, Inc.