Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Retention in treatment
[41] Systematic review	30 people Data from 1 RCT	Completion of detoxification 15/15 (100%) with antagonist-induced withdrawal 8/15 (53%) with tapered methadone	RR 1.82 95% CI 1.14 to 2.91 P = 0.012	Small effect size	antagonist-induced withdrawal
[41] Systematic review	70 people Data from 1 RCT	Completion of detoxification 28/36 (78%) with antagonist-induced withdrawal 21/34 (62%) with clonidine	RR 1.26 95% CI 0.92 to 1.73 P = 0.15		Not significant