Washton 1981.

Methods	Randomised, placebo‐controlled, double‐blind trial. May include some participants from multicentre study ‐ see Senay 1983
Participants	Setting: outpatient, New York, USA. Participants: 26 withdrawing from methadone maintenance (n = 19) or heroin or methadone or both (n = 7). Group sizes: 13 in each group. Groups stated as similar. Mean age: 31 years. 85% men. Mean duration of addiction 10 years
Interventions	Stabilised for 3 weeks on methadone 15 to 30 mg/day, then: (1) Clonidine, dose titrated against symptoms and side effects to max 1.2 mg/day. (2) Methadone reduced by 1 mg/day. Clinic visits 3 to 5 times per week. Scheduled duration of study intervention 30 days
Outcomes	Number achieving 10 days opioid free; number initiating naltrexone maintenance treatment
Notes	Ratings of withdrawal not reported. Partial support from National Institute on Drug Abuse
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Subjects were randomly assigned." Comment: Method of sequence generation not reported and insufficient information on group characteristics to make a judgement on adequacy
Allocation concealment (selection bias)	Unclear risk	Method not reported
Blinding (performance bias and detection bias) Subjective outcomes ‐ intensity of withdrawal, adverse effects	Low risk	Participants and investigators blind to medication. Investigators not informed of blood pressure measurements to avoid breaking blind
Blinding (performance bias and detection bias) Objective outcomes ‐ duration of treatment, completion of treatment	Low risk	Participants and investigators blind to medication. Investigators not informed of blood pressure measurements to avoid breaking blind
Incomplete outcome data (attrition bias) All outcomes	Low risk	Completion of treatment is the only outcome included in analyses for this review. Drop‐out was not clearly reported
Selective reporting (reporting bias)	Low risk	None apparent
Other bias	Low risk	None apparent