Prescription pain medications and chronic headache in Denmark: implications for preventing medication overuse.

PURPOSE: The aim of the present paper is to study which prescription pain medications are most commonly dispensed to people with chronic headache (CH), particularly those with medication-overuse headache (MOH).

METHODS: This cross-sectional study analysed prescription pain medications dispensed within 1 year to 68,518 respondents of a national health survey. Participants with headache ≥ 15 days per month for 3 months were classified as having CH. Those with CH and over-the-counter analgesic use ≥ 15 days per month or purchase of ≥ 20 or ≥ 30 defined daily doses (DDDs) of prescription pain medication per month (depending on the drug) were classified as having MOH. Associations between CH and other chronic pain conditions were analysed by logistic regression.

RESULTS: Among those with CH (adjusted prevalence 3.3%, CI 3.2-3.5%), pain medications most commonly dispensed were paracetamol, tramadol, ibuprofen and codeine. CH was associated with osteoarthritis, back pain, and rheumatoid arthritis. Among those with MOH, 32.4% were dispensed an opioid at least once within 1 year. Only 5.1% of people with CH were dispensed triptans.

CONCLUSIONS: High prevalence of opioid use among people with CH may be due to inappropriate headache treatment or development of MOH among those treated for other pain conditions. While there were cases of triptan overuse, triptans remain underutilized among those with CH, suggesting that migraine may be under-recognized and inappropriately treated, leading to overuse of other medications. Education of physicians on appropriate headache management is essential for MOH prevention. There is a need to increase universal awareness about MOH as an adverse effect of long-term analgesic use.