Deaths due to abuse of dextromethorphan sold over-the-counter in Pakistan

Abstract

Dextromethorphan is the most commonly used over-the-counter anti-tussive and expectorant medicine at therapeutic doses. Due to easy availability, euphoric high and hallucinogenic effects at larger doses, dextromethorphan popularity amongst the drug abusers is growing day by day. It is often mixed with alcohol, opiates, cannabinoids or other drugs of abuse for recreational purposes despite their lethal synergistic effects. More than 50 deaths were reported the first time in Pakistan after consuming cough syrups containing dextromethorphan, manufactured by two local pharmaceutical industries. All deceased had the history of drug abuse. We report the deaths of nineteen males, ages ranged from 17 to 45 years, in two major cities of Pakistan who purposefully ingested large doses of dextromethorphan for recreational purposes and died as a result of direct toxic effects of the drug. Toxicological analysis revealed high levels of dextromethorphan ranging from 7.3 to 41.7 mg/L in the peripheral blood, 4.2–92.6 mg/kg in the liver and 9.9–349.6 mg/L in the gastric content by high performance liquid chromatography. The dextromethorphan concentrations in all subjects significantly exceeded the therapeutic range and were consistent with concentrations reported in other cases of dextromethorphan abuse and toxicity. Besides dextromethorphan other drugs of abuse like cannabinoids, opiates, benzodiazepines, ethanol and chlorpheniramine were also detected. The cause of death was determined to be acute dextromethorphan intoxication with lethal synergistic effect of other co-ingested drugs of abuse. The deaths resulted in the prosecution of all individuals involved in manufacturing, distribution or sale of the cough syrup.

Keywords

• Dextromethorphan
• Liquid chromatography
• Synergistic effect