Effect of add-on amantadine to clonidine on opioid withdrawal symptoms in opioid-dependent patients detoxified with buprenorphine: a randomized controlled trial

Objective This research aimed to assess the effectiveness of combination therapy with amantadine and clonidine against clonidine alone on subjective opioid withdrawal symptoms in patients treated with buprenorphine. Methods and Materials Patients were recruited from outpatient addiction treatment centers for this double-blind, randomized control trial. They were divided into two groups randomly assigned to receive either clonidine (0.15-0.3 mg/day) or clonidine with amantadine (100-200 mg/day). We assessed withdrawal symptoms with the Subjective Opiate Withdrawal Scale (SOWS) on the first day of admission and 3, 7, 14, and 21 days afterward. Results Forty-three patients completed the trial in each group. The impact of adding-on amantadine on the mean SOWS compared to control was significant (p < .001) at any time of the study period. However, there were no significant differences in mean SOWS within groups during follow-up (p > .05). Also, there were no significant differences in mean SOWS between the two groups during follow-up time (day 3rd, 7th, 14th, and 21st) (p > .05). Conclusion Amantadine and clonidine combined treatment would result in fewer opioid withdrawal symptoms than clonidine alone, with a decrease commencing on the third day.