Abstract
Background: Recently, concern has been raised in Danish media regarding tramadol's addictive properties. To assess whether use of tramadol is of national public health concern, we examined the prevalence of tramadol users in Denmark, and compared it with Norway and Sweden.
Methods: The cohort constitutes the entire population of Denmark, Norway, and Sweden, between 2007 and 2015. We used information from the three publicly available national prescription databases to assess the prevalence of tramadol and other opioids (to analyze possible exposure-switch).
Results: The prevalence of tramadol increased between 2007 and 2015 in Denmark from 4.5% to 5.2%, and in Norway from 2.0% to 4.1%, while it decreased in Sweden from 3.6% to 1.7%. During the same time period, the prevalence of other opioids remained steady in Denmark at around 4%, while it decreased in Norway from 9.4% to 8.5%, and increased in Sweden from 5.9% to 7.7%. The average defined daily dose (DDD) per treated patient per year remained fairly steady during the time period in Denmark and Norway, while it increased approximately 50% in Sweden. Interestingly for tramadol, the average DDD per treated patient per year was higher for women compared with men for Denmark and Norway, but not for Sweden.
Conclusion: We saw an increase in prevalence of tramadol exposure in Denmark and Norway, and a decrease in Sweden. The changes in Norway and Sweden can possibly be attributed to a change in use to other opioids. Further studies are needed to explain the changes and the considerable differences between the Nordic countries and between genders. Importantly, the prevalence calls for studies assessing its consequences and risk of addiction.
