Background: The various benzodiazepines have essentially the same mechanism of action and differ from one another primarily through differences in pharmacokinetics. There is no pharmacological basis for using more than one benzodiazepine for the same patient. The purpose of the study was to examine the occurence of co-medication with different types of benzodiazepines in Norway.
Material and method: Data were obtained from the Norwegian Prescription Database. Patients who received at least one benzodiazepine in 2008 were included (n = 299,185). The percentage of users who were co-medicated with at least two different benzodiazepines and the amounts prescribed were calculated and stratified by gender and age.
Results: It is highly probably that 27,861 (14,6%) of patients who received at least two benzodiazepines in the course of 2008 used two different benzodiazepines simultaneously. 13,267 (6.9%) of the patients were prescribed at least two different benzodiazepines on the same prescription. A larger number of women were co-medicated with different benzodiazepines, but the proportion of comedication was higher in men than in women, and most frequent in the age group 18-49 years.
Interpretation: There is an extensive and unfortunate prescription practice whereby the same patient is prescribed different benzodiazepines that are used concurrently. Patients who use different benzodiazepines concurrently are mainly prescribed these by one and the same doctor.