Suvorexant as an Adjunctive Treatment for Insomnia Prior toDiscontinuation of Benzodiazepines: Prevention of Withdrawal Syndromeand Rebound Insomnia

Objective: To examine whether concurrent use of benzodiazepines (BZDs) affects continuation rates for suvorexant. Background: A wider range of different BZDs and similar drugs are available on prescription in Japan than in other countries, making prescribing more complicated. Safety has only been indicated for the use of suvorexant as monotherapy in primary insomnia. Understanding the safety of concurrent use of suvorexant with other drugs could simplify prescriptions for insomnia. Material and Methods: We obtained the prescription records of patients who were hospitalized or attended outpatient appointments, and were prescribed suvorexant, at Showa University Karasuyama Hospital between November 2014 and April 2016. Results: Patients prescribed suvorexant were retrospectively surveyed for drug discontinuation as indicated in their medical records. Among 326 patients who were prescribed suvorexant during the study period, use of the medication could not be confirmed in 20 patients, who were therefore excluded. This left a final study sample of 306 patients. We could track 289 patients up until day 90. There were no significant differences observed between patients treated with a BZD combination (54.0%) and those not treated with a combination (46.0%) in terms of medication continuation across the 90-day observation period (Exp(B)=1.304, 95% confidence interval, CI: 0.827-2.057, P=0.253). The rates of side effect onset were also not significantly different. Conclusion: We observed that concurrent use of BZD was not related to withdrawal from suvorexant in patients being treated for insomnia.