An open trial of naltrexone for opiate dependence

The objective of this study was to conduct a pilot study of naltrexone in opiate-dependent patients in order to determine the sample size for a double-blind controlled trial, to identify possible confounders and to obtain experience with the drug's side effects and acceptability to patients. Opiate-dependent patients presenting to a public hospital for treatment for their dependence were invited to participate. Patients with major organic illness, another Axis I diagnosis, or who were pregnant were excluded. Naltrexone was prescribed at a dose of 50 mg daily for 6 months. Data were collected on drug use, social stability, physical and mental health before during and after the treatment programme. Patients were seen weekly for 6 months then monthly for a further 6 months. Forty-four patients were enrolled, but three stopped naltrexone early because of possible side effects. Of the remainder, 32 were followed for at least 12 months. Eight (25%) ceased opiate use from the start, and another two were no longer using at the end of 12 months giving an abstinence rate of 31% at 12 months. Retention in treatment was 34%. Of the abstinent patients however, only two took naltrexone for the whole 6 months. Naltrexone was well tolerated and associated with a significant abstinence rate, but most patients do not feel they need to take the drug for 6 months. A double-blind controlled trial would be justified.