Use of codeine analgesics in a general population. A Norwegian study of moderately strong analgesics

The prescribing of controlled analgesics (codeine, buprenorphine and pentazocine preparations) was studied, using prescriptions from the three pharmacies in the municipality of Tromsø, Norway. All prescriptions dispensed during one year were analysed. The study sample comprised 3083 women (58%) and 2223 men (42%) between 10 and 99 years of age. About 8% of the population had obtained one or more prescriptions of controlled analgesics. Combined codeine preparations were by far the most frequently prescribed subgroups, and the average amount purchased during 1 year was 30 defined daily doses (DDD). The sporadic users were in the majority. A few users had purchased high amounts of controlled analgesics. The prevalence of use, the mean number of defined daily doses of analgesics, and the proportion of 'weekly' drug users was higher in women than men. The prevalence increased significantly with age, from 0.7 to 22.3% in women and from 0.5 to 14.1% in men. The mean number of DDD during one year also increased with age, from 12.6 to 50.6 DDD in women, and from 6.6 to 40.6 DDD in men. The users of buprenorphine and pentazocine differed in several aspects from the codeine users. The highest use of combined codeine preparations was seen in elderly people especially in women. Use of lower codeine doses or intermittent treatment with other drugs e.g. plain paracetamol in adequate doses, may be appropriate alternatives reducing the risk of adverse drug reactions such as nausea and constipation. Monitoring of prescribing and use of controlled analgesics according to certain criteria may uncover possible misuse.