Comparison of 2 Naltrexone Regimens in the Maintenance Therapy of Acute Methadone Overdose in Opioid-Naïve Patients: A Randomized Controlled Trial

Substituting antidotes with longer half-lives may decrease the danger of unobserved respiratory depression in opioid overdose. The present triple-blind controlled trial aimed to compare two different doses of naltrexone (i.e., 50 vs. 100 mg) in the maintenance therapy regarding methadone-overdosed in opioid-naïve patients. Seventy opioid-naïve methadone-intoxicated patients with a mean age of 26 ± 9 years were prospectively included in this study and were treated with naloxone. They were then consecutively assigned to A or B groups (including 35 patients each) receiving 100- and 50-mg naltrexone capsules, respectively. The patients were followed for 48 hours in the hospital and re-evaluated by a phone call follow-up after discharge. Finally, they were compared regarding re-development of the toxicity signs and symptoms, a need for re-administration of naloxone, and the final outcome. Based on the results, only diastolic blood pressure, serum bicarbonate, and base excess were significantly different between the groups. During hospitalization, one patient in group A experienced apnea while none of the patients in group B had such an experience (P > 0.05). In addition, in follow-up evaluations and after the hospital discharge, the mean venous blood gas (VBG) parameters were found to be identical between both groups. Hospitalization period was similar (all P values were greater than 0.05). In general, 2 different 50- and 100-mg regimens of naltrexone have the same efficacy in preventing the apnea and respiratory depression in methadone-intoxicated opioid-naïve patients. However, the 50-mg dose is the superior regimen recommended in this respect.