Analgesic use in a Norwegian general population: change over time and high-risk use--The Tromsø Study.

backgroundIncreased use of analgesics in the population is a cause for concern in terms of drug safety. There is a paucity of population-based studies monitoring the change in use over time of both non-prescription (OTC) analgesics and prescription (Rx) analgesics. Although much is known about the risks associated with analgesic use, we are lacking knowledge on high-risk use at a population level. The purpose of this study was to estimate the prevalence of non-prescription and prescription analgesic use, change over time and the prevalence in the presence of potential contraindications and drug interactions in a general population.

methodsA repeated cross-sectional study with data from participants (30-89 years) of the Tromsø Study in 2001-02 (Tromsø 5; N = 8039) and in 2007-08 (Tromsø 6; N = 12,981). Participants reported use of OTC and Rx analgesics and regular use of all drugs in the preceding four weeks. Change over the time period was analyzed with generalized estimating equations. The prevalence of regular analgesic use in persons with or without a clinically significant contraindication or drug interaction was determined in the Tromsø 6 population, and differences were tested with logistic regression.

resultsAnalgesic use increased from 54 to 60% in women (OR = 1.24, 95% CI 1.15-1.32) and from 29 to 37% in men (OR = 1.39, 95% CI 1.27-1.52) in the time period; the increase was due to sporadic use of OTC analgesics. There was substantial regular use of analgesics in several of the contraindication categories examined; the prevalence of non-steroidal anti-inflammatory drugs was more than eight per cent among persons with chronic kidney disease, gastrointestinal ulcers, or high primary cardiovascular risk. About four per cent of the study population demonstrated at least one potential drug interaction with an analgesic drug.

conclusionsThe use of analgesics increased in the time period due to an increase in the use of OTC analgesics. Analgesic exposure in the presence of contraindications or drug interactions may put patients at risk. Public and prescriber awareness about clinically relevant contraindications and drug interactions with analgesics need to be increased.