Tramadol use in Norway: A register-based population study.

PURPOSE: Increasing use of tramadol for chronic non-cancer pain is concerning since tramadol users may be at risk of developing recurrent opioid use with increasing opioid consumption and co-medication. Therefore, we investigated a complete national cohort of tramadol users.

METHODS

The study population (154 042 adult individuals in Norway, who redeemed ≥ one tramadol prescription in 2012) was stratified into four groups according to their opioid use 2 years before their first tramadol prescription in 2012 and followed until 2016. Information on all dispensed opioid analgesics, benzodiazepines (BZDs), and BZD-related Z-hypnotics were retrieved from the Norwegian Prescription Database.

RESULTS

Six percent of opioid naïve tramadol users (no opioid use 2 years before tramadol use in 2012) became recurrent users (received opioids annually during 4-year follow-up), almost doubled their mean opioid consumption (66 to 108 defined daily doses [DDD]). One-quarter proceeded to strong opioids or was co-medicated with BZDs, one-third with Z-hypnotics. Among former weak opioid users, 39.8% became recurrent users, 18.7% proceeded to strong opioids, mean opioid consumption increased slightly, one-third used BZDs, or Z-hypnotics concurrently. Among former strong opioid and users in palliative care; 61%, 70% became recurrent users and developed a similar prescription pattern (high and increasing mean opioid consumption, 301 to 318, 413 to 430 DDD); half of them proceeded to strong opioids and/or used BZDs or Z-hypnotics concurrently.

CONCLUSIONS

Many patients who developed recurrent opioid use received prescriptions which substantially conflicted with existing guidelines and might lead to problematic opioid use.