Evaluating the Safety of Acute Baclofen in Methadone-maintained Individuals With Opiate Dependence.
Status:
Not yet recruiting
Trial end date:
2022-09-01
Target enrollment:
Participant gender:
Summary
Opiate addiction is a major health challenge. The mainstay of treatment is opiate
substitution therapy (OST), typically methadone, but many desire to be opiate-free.
Abstinence in older opiate addicts with increasingly complex health needs may also be
advantageous. Detoxification generally involves tapering of OST with adjunct medication to
treat emerging symptoms, but these are often ineffective or inappropriate for longer-term
prescribing. New treatments are therefore needed. The investigators propose that baclofen has
the desired properties to facilitate OST detoxification. It is licensed for spasticity, is
currently used to treat alcoholism and there is promising pre-clinical and clinical evidence
of potential efficacy in opiate dependence. Common symptoms of withdrawal are likely to be
improved by baclofen. Whilst the investigators clinical experience and other studies suggest
baclofen can be taken safely with methadone, they could potentially interact causing adverse
effects such as respiratory depression. Also, the possibility of abuse liability remains
unexplored and is an important consideration in this indication. The investigators will
therefore determine the safe dose combinations of baclofen and methadone and to assess if
baclofen is 'liked'. Patients engaged in treatment for opiate dependence from community
addiction services and receiving stable doses of OST with methadone will be invited to
undergo screening at the Imperial Clinical Research Facility (ICRF) at Hammersmith hospital,
or at their local addiction clinic. Up to 64 eligible patients will attend the ICRF for an
experimental visit. Acute baclofen or placebo will be orally administered (randomised,
single-blind, 3:1 ratio respectively) with the dose determined by a Bayesian adaptive trial
algorithm. Measures will comprise respiratory, sedation, self-report and cardiovascular
monitoring, and blood sampling for 5 hours post-dose. The study duration will be ~2-3 weeks
from pre-screening phone call to the post visit follow up phone call.