A comparative study of the efficacy of venlafaxine and naltrexone for relapse prevention in patients with opioid use disorder attributed to tramadol.

Tramadol and venlafaxine share similar pharmacological characteristics that may allow for overlapping therapeutic indications for them. The objective of this study was to compare the efficacy of venlafaxine and naltrexone in the treatment of tramadol abuse. This comparative trial included 95 patients with tramadol abuse who were detoxified for 2 weeks. Twenty-eight participants underwent the maintenance phase, while the remaining participants (n = 67) dropped out. The patients were randomized to use 50 mg/day of naltrexone or 225 mg/day of venlafaxine for 8 weeks. All participants were interviewed using SCID-I (DSM-IV-TR) criteria for diagnosing substance use and other psychiatric disorders. The proportion of relapsed patients was comparable between the naltrexone and venlafaxine groups (29.4% vs. 30.4%, P  = 0.9). However, participants in the venlafaxine group stayed in treatment longer than participants in the naltrexone group, and the difference was significant (22.9 ± 7.89 days vs. 16.9 ± 3.4 days, P = 0.01). Only psychiatric comorbidity was found to be significantly associated with retention in treatment (80% vs. 22%, P  = 0.005). Venlafaxine is as effective as naltrexone in preventing relapse in patients with tramadol abuse. Venlafaxine was more effective than naltrexone in treatment retention.