Background: Methadone for opiate substitution was available only in syrup formulation prior to 2008. In 2007, the French Health Authorities made solid forms available. A national survey was performed in order to evaluate the modification of child poisonings induced by such a new pharmaceutical formulation.
Methods: A prospective study was set up (April 15, 2008 to April 15, 2014) with the analysis of cases of unintentional ingestion of methadone by patients under 18 years old and managed by the 10 French poison control centers at the national level. As soon as a new pediatric exposure was recorded in the informatics data bank of the Poison Centers, a telephone survey was performed by the Marseilles' Poison Center to obtain the evolution and all the necessary details.
Results: 87 cases of child poisonings with the 2 forms were reviewed (syrup, 56 patients; capsules, 31 patients). Comparison shows that patients were similar for both formulations (no significant difference concerning age [median 2 years], sex ratio [M/F 0.85], previous history, and ingested quantities of methadone). There was a similar severity profile with both formulations proving that methadone can lead to lethal child intoxications (1 death with capsules and 4 with syrup). The relative risk of pediatric accidents is also the same with 2 formulations, leading the health authorities, in collaboration with laboratories, to design and distribute flyers. The aim was to inform patients who are also parents about the high danger risk of their treatment for children, whatever the formulation of methadone present in the house.
Discussion: The results of this survey were similar to those of another national study by the French Poison Centers concerning adult suicide attempts with methadone. Both prospective studies led to the conclusion that methadone must be considered as a dangerous molecule for patients and their families. The recent availability of a solid formulation in France did not change the profile of poisonings with this opiate substitute treatment.
Keywords: Child poisoning; Methadone; Poison centers.