Toxicological Relevance of Pregabalin in Heroin Users: A Two-Year Postmortem Population Study

Area of Science:

• Forensic Toxicology
• Pharmacology
• Addiction Medicine

Background:

• Pregabalin (PGL), a gabapentinoid, is prescribed for epilepsy, neuropathic pain, and anxiety disorders.
• PGL is misused by heroin users to enhance heroin's effects, but comparative usage levels are unknown.
• This study investigates differences in PGL concentrations between heroin and non-heroin users in postmortem samples.

Purpose of the Study:

• To determine if postmortem pregabalin (PGL) concentrations are significantly higher in heroin users compared to non-heroin users.
• To explore correlations between PGL and heroin (morphine) concentrations in heroin users.
• To identify co-administered substances in heroin users who tested positive for PGL.

Main Methods:

• Analysis of 3,750 postmortem femoral-vein blood samples from January 2016 to December 2016.
• Routine drug screening and specific pregabalin (PGL) screening were performed.
• Comparison of PGL concentrations between 69 heroin users and 160 non-heroin users positive for PGL, with 264 heroin users as controls.

Main Results:

• Statistically significant higher PGL concentrations were found in heroin users compared to non-heroin users (P=0.002).
• No correlation was observed between PGL and morphine concentrations in heroin users (P=0.95).
• Heroin users positive for PGL showed significantly higher co-use of antidepressants, benzodiazepines, methadone, and other opioids (P<0.001).

Conclusions:

• Heroin users consume greater amounts of pregabalin (PGL) than non-heroin users.
• The increased PGL use in heroin users may not significantly elevate PGL toxicity risk alone.
• Heroin users taking PGL are more likely to use multiple depressant drugs, increasing the risk of combined toxicity and death.