Long-term Use of Z-Hypnotics and Co-medication with Benzodiazepines and Opioids

Abstract

Benzodiazepine-like drugs (z-hypnotics) are the most commonly used drugs for treatment of insomnia in Norway. Z-hypnotics are recommended for short-term treatment not exceeding 4 weeks. We aimed to study the use of z-hypnotics in the adult population in Norway with focus on recurrent use in new users, treatment intensity and co-medication with benzodiazepines and opioids in long-term users. Data were obtained from the Norwegian Prescription Database. New users in 2009 were followed through 2013. Recurrent z-hypnotic use was defined as new fillings at least once in each of the four 365-day follow-up periods. Age groups of 18-39, 40-64 and 65+ years were analysed separately for men and women. In 2013, 354,571 (8.9%) of the population filled at least one prescription of z-hypnotics and the prevalence was relatively stable over time. Among the 92,911 new users of z-hypnotics in 2009, 13,996 (16.8%) received z-hypnotics all four 365-day periods of follow-up. In these long-term recurrent users, the treatment intensity was high already the second year, with mean annual amounts of 199 and 169 DDDs per patient in men and women, respectively. The interquartile differences were greatest in the youngest age group. 27.9% of the long-term recurrent users of z-hypnotics used benzodiazepines the fourth year and 33.9% used opioids. The proportions with co-medication increased with level of z-hypnotic treatment intensity. Overall, many z-hypnotic users had medicines dispensed for longer periods than recommended, and co-medications with drugs that may reinforce the central depressing and intoxicating effects were common.