Effectiveness of Dihydrocodeine (DHC) in reducing illicit opiate use

In a systematic review investigating the effectiveness of Dihydrocodeine in reducing illicit opiate use: 

• Two studies with 150 individuals compared DHC with buprenorphine for detoxification and found low-quality evidence of no significant difference between DHC and buprenorphine for detoxification at six-month follow-up (RR 0.59, 95% CI 0.25 to 1.39; P = 0.23) in the meta-analysis for the primary outcome of abstinence from illicit opiates. Similarly, low-quality evidence indicated no difference for treatment retention (RR 1.29, 95% CI 0.99 to 1.68; P = 0.06).
• One study with 235 participants compared DHC to methadone for maintenance substitution therapy resulting in low quality evidence, and possibly no difference in effects between DHC and methadone for reported abstinence from illicit opiates (MD −0.01, 95% CI −0.31 to 0.29). For treatment retention at six months' follow-up in this single trial, the RR calculated with an intention-to-treat analysis also indicated that there may be no difference between DHC and methadone (RR 1.04, 95% CI 0.94 to 1.16).

It is  premature to make any conclusive statements about the effectiveness of DHC and further high-quality studies are needed, especially in low- to middle-income countries.