Fatal pregabalin poisoning in Japan: A case report

Pregabalin is a new drug used for treating neuropathic pain, epilepsy, and anxiety disorders. Since 2010, the number of pregabalin prescriptions has dramatically increased in many countries. Although pregabalin has been considered to have a low potential for abuse and toxicity, fatal cases associated with pregabalin misuse or abuse have been increasing with an increased number of prescriptions. In addition, these fatalities are likely under-reported because pregabalin is commonly not part of postmortem routine drug screens. By contrast, pregabalin-related death has not yet been reported in Japan. We encountered a fatal case of pregabalin overdose. The patient has visited hospitals for benzodiazepine dependence, insomnia and anxiety disorder and has been prescribed pregabalin, flunitrazepam, and zolpidem. One day, his home caregivers, who were his constant companions to the hospitals, found him dead. Comprehensive drug screening performed in the police crime laboratory detected 7-aminoflunitrazepam and zolpidem, but not pregabalin in the cardiac blood. By contrast, we could find all drugs, including pregabalin, in our autopsy because pregabalin was a part of our routine drug screening. The pregabalin concentration was fatal at 18.5 μg/mL in the femoral blood, whereas 7-aminoflunitrazepam (0.1 μg/mL) and zolpidem (0.2 μg/mL) were lower than the fatal levels. We concluded that pregabalin played a primary role in the cause of death but not independently. This report addresses Japanese clinicians and forensic toxicologists to the risk of pregabalin poisoning, and pregabalin should be added in postmortem routine drug screening.