Suicidal poisonings with methadone in France: Results of a two year national survey by the Toxicovigilance Network

Abstract

Context. Methadone is used in France since March 1995, only for opioid maintenance treatment, in a syrup form. For the launching of a capsule form in April 2008, French health authorities requested a prospective survey of all cases involving exposure to methadone in either of the two available pharmaceutical forms. Objective. The aim was to document, in different circumstances and compare the safety of the new capsule form to the syrup. This report presents the findings of one arm of the study, devoted to methadone-related suicide attempts. Materials and method. From April 15, 2008 to April 15, 2010, all self-injurious methadone poisonings notified to or managed by the French Toxicovigilance Centers network were included. Analysis mainly focused on patients’ age and gender, estimated quantity ingested, eventual concomitantly taken substances, distribution of symptoms, and site of treatment. Results. 135 methadone-related suicide attempts were recorded. Analysis showed identical epidemiologic and clinical patient characteristics for the two pharmaceutical forms. Ten deaths occurred. The only discrepancy was a higher incidence of suicide attempts in the capsule group. However, as the number of capsule-treated patients increased during the second year, this difference remained significant but tended to decrease. Discussion. Combining these results with Pharmacovigilance and Addictovigilance arms, health authorities estimated that the benefit/risk balance of this new pharmaceutical form remains positive. They revised their position on requirements for prescribing and dispensing of the capsule form, and made them slightly easier. Following this, this “suicide” arm of Toxicovigilance survey was suspended, whereas the second one, concerning accidental pediatric methadone-related poisonings, has been extended until April 2014. Conclusion. In France, suicide attempts were more likely to occur with the capsule formulation. The clinical severity of intoxication was similar between the capsule and liquid forms.