Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Retained in naltrexone maintenance or abstinent
[41] Systematic review	30 people Data from 1 RCT	Retained in naltrexone maintenance or abstinent 12 weeks 10/15 (67%) with antagonist-induced withdrawal 5/15 (33%) with tapered methadone	RR 2.00 95 % CI 0.90 to 4.45 P = 0.09		Not significant
[41] Systematic review	240 people 3 RCTs in this analysis	Retained in naltrexone maintenance or abstinent 12 weeks 26/122 (21%) with antagonist-induced withdrawal 9/118 (8%) with clonidine	RR 2.77 95% CI 1.37 to 5.61 P = 0.004	Moderate effect size	antagonist-induced withdrawal
[41] Systematic review	72 people Data from 1 RCT	Retained in naltrexone maintenance or abstinent 12 weeks 7/35 (20%) with antagonist-induced withdrawal 9/37 (24%) with buprenorphine	RR 0.82 95% CI 0.34 to 1.97 P = 0.66		Not significant