A randomized investigation of methadone doses at or over 100 mg/day, combined with contingency management

Methadone maintenance for heroin dependence reduces illicit drug use, crime, HIV risk, and death. Typical dosages have increased over the past few years, based on strong experimental and clinical evidence that dosages under 60 mg/day are inadequate and that dosages closer to 100mg/day produce better outcomes. However, there is little experimental evidence for the benefits of exceeding 100 mg/day, or for individualizing methadone dosages. We sought to provide such evidence.

We combined individualized methadone dosages over 100 mg/day with voucher-based cocaine-targeted contingency management (CM) in 58 heroin- and cocaine-dependent outpatients. Participants were randomly assigned to receive a fixed dose increase from 70 mg/day to 100mg/day, or to be eligible for further dose increases (up to 190 mg/day, based on withdrawal symptoms, craving, and continued heroin use). All dosing was double-blind. The main outcome measure was simultaneous abstinence from heroin and cocaine.

We stopped the study early due to slow accrual. Cocaine-targeted CM worked as expected to reduce cocaine use. Polydrug use (effect-size h=.30) and heroin craving (effect-size d=.87) were significantly greater in the flexible/high-dose condition than in the fixed-dose condition, with no trend toward lower heroin use in the flexible/high-dose participants.

Under double-blind conditions, dosages of methadone over 100mg/day, even when prescribed based on specific signs and symptoms, were not better than 100mg/day. This counterintuitive finding requires replication, but supports the need for additional controlled studies of high-dose methadone.