Safety and efficacy of phenobarbital for benzodiazepine detoxification

Objective: Benzodiazepine (BDZ) efficacy and safety profile present clinical issues such as memory impairment, dependence and abuse (1). Withdrawal symptoms can vary from simple rebound anxiety to life threatening seizures. Severity is associated with short-acting BDZ, prolonged or high-dose use (2). Although multiple clinical approaches, limited data are currently available on safety and effective of BDZ detoxification protocols. A fixed-dose phenobarbital taper, a long-acting cross-tolerant medication, has been used by our Clinical Toxicology Unit for 30 years. We undertook this study to formally investigate its safety and effectiveness. Methods: Using our database, a retrospective study has been carried out in order to evaluate all patients treated with fixed-dose phenobarbital taper for BDZ detoxification from January 2006 to December 2012. The primary outcomes, assessed during hospital stay and at 1st and 12th months after discharge, were safety, tolerability and efficacy of protocol. Results: Over 6-year observation period 213 patients were treated, median age 41 years, 60% male (n=129). 46% (n=98) patients were solely addicted to BDZ while 54% (n=115) had a concomitant abuse with alcohol, opioids or both. Overall, 12 different BDZ were abused, being lormetazepam the most commonly used (n=84, 32%). Psychiatric comorbidity was found in 76% (n=162), with anxiety and depression disorders as the most prevalent. No major adverse phenobarbital side effects were observed and no patients showed any severe BDZ-related withdrawal syndrome. Average hospital length of stay was 8.5 days. All patients were treated initially with 50-100 mg phenobarbital every 8 hours, on the basis of referred abuse and adjusted on account of symptoms. Phenobarbital was progressively tapered during the hospitalization and rehabilitation. The tolerability of the protocol was confirmed by the low drop-out rate (10%, n=22). At time of discharge, 70% (n=132) of patients were completely BDZ-free. Phenobarbital was completely dropped out in a three month period. Analyzing the relapse rate of the treated patients during 2011-2012 years, 70% (n=32) maintained a BDZ free status at 12 month follow up. Conclusion: Our study suggests that phenobarbital detoxification is a good choice for patients with BDZ dependence on the basis of the efficacy (low relapse rate), safety (no major adverse effect) and tolerability (low drop-out).