New formulation of methadone for opioid dependence in France: acceptability and diversion/misuse liability.

A new formulation of methadone as capsules is marketed in France since 2008. Few data are available on the patient acceptability and the risk of misuse of this new formulation. To assess the patient acceptability after the switch methadone syrup/capsules and the diversion/misuse liability of the methadone capsule, a study through an anonymous questionnaire was conducted between March 2011 and May 2012 in two methadone centers of the region. Forty-one patients (men 75.6%) participated, with a median age of 37 years [IQR: 33-43 years]. The median duration of syrup methadone maintenance therapy was 1 year [IQR: 1-3 years]. A majority of patients (80.5%) described side-effects due to the syrup formulation. Median daily dose at the switch to methadone capsules was 75 mg [IQR: 42-105 mg]. Six patients described differences in the pharmacologic effect between the two formulations. Concerning the diversion and misuse liability of methadone capsules, 26.8% of patients reported that the medication was available at the "street market". Three patients have tried to solubilize and eight have tried to snooze it. All patients recognize the contribution of this new formulation concerning the use, side-effects and transport. None of them returned to the syrup.