Lethal methadone intoxications in Geneva, Switzerland, from 1994 to 1998.

AIMS: To estimate the number of methadone lethal intoxications in Geneva from 1994 to 1998, where the number of patients in methadone treatment has more than doubled since 1990.
DESIGN: Retrospective study of all toxicological, autopsy and clinical data.
SETTING: The Geneva Department of Forensic Medicine. PARTICIPANTS: All suspected overdose deaths in Geneva from 1994 to 1998. Cases were selected on the basis that the only cause of death was a potentially lethal drug concentration in the postmortem blood sample. MEASUREMENT: Toxicology and autopsy findings, clinical and drug history.
FINDINGS: There were 106 lethal drug intoxications over the period. The overall number of drug intoxication deaths went from 33 in 1994 to nine in 1998. Thirty-six cases had methadone identified in their blood. All the 36 cases but one had medications or other drugs used illicitly present in the blood or urine. Of these 36 cases, 21 were attributed to methadone lethal intoxication. Only seven of these 21 decedents were enrolled in a methadone programmes. The number of deaths attributed to methadone intoxication ranged from three to five per year.
CONCLUSION: Most lethal methadone intoxication is due to diverted or illegal methadone in association with medications or other drugs used illicitly. Furthermore, the increase in methadone prescription under strict medical control with health measures aimed at drug abuse prevention did not lead, in our study, to an increase of methadone lethal intoxication and may have been partly responsible for the large decrease of overall drug intoxication deaths during the time of our study.