Continuous versus non-nightly use of zolpidem in chronic insomnia: results of a large-scale, double-blind, randomized, outpatient study

New treatment strategies are encouraged in insomnia and, in particular, discontinuous treatment. The aim of this double-blind study was to compare, in a large primary care population of chronic insomniacs (>4 weeks duration) the efficacy and safety of zolpidem 10 mg 5 nights/week and placebo 2 nights/week, to that of nightly zolpidem. Seven hundred and eighty-nine drug-free insomniacs, with a Total Sleep Time (TST) of 3-6 h/night were enrolled in seven European countries. After a placebo run-in period, treatment lasted 14 days. The primary criterion was the Clinical Global Impression improvement score (CGI-II) which showed that 65.2% of patients in the continuous and 58.6% in the discontinuous groups were rated 'much' or 'very much' improved. Even though the non-inferiority test did not show the equivalence of both regimens, the difference of 7% in responder rates does not appear to be clinically relevant. Other sleep parameters such as TST, number of nocturnal awakenings and Quality of Life scales showed marked, not significantly different, improvements in both groups. Both regimens were well tolerated and no adverse event which could be related to non-treatment nights was reported in the discontinuous group. Non-nightly zolpidem appears to be a feasible and safe additional option for the management of chronic insomnia. Int Clin Psychopharmacol 17:9 17 (C) 2002 Lippincott Williams Wilkins.