Chronic Migraine Strongly Linked With Analgesic Overuse

Reuters Health-May 18,2004

Chronic migraine is more strongly linked to analgesic overuse than are other chronic pain conditions, such as neck and low-back pain, according to a new report.

The findings are based on a study of more than 49,000 subjects in Norway who completed questionnaires about chronic pain conditions and analgesic use.

Overall, 1% of subjects who used analgesics daily or almost daily for at least 1 month reported having a chronic headache, defined as 15 or more days per month with headache, lead author Dr. J.-A. Zwart, from the Norwegian University of Science and Technology in Trondheim, and colleagues note.

Among subjects who reported analgesic overuse for at least 3 months, the prevalence of chronic headache was 0.9%. The rate in women was 1.2%, double that seen in men.

Analgesic overuse for at least 1 month increased the risk of chronic headache 7.5-fold, the authors note in the May 11th issue of Neurology.

Among various chronic pain conditions, analgesic overuse was most strongly linked to chronic migraine, followed by non-migraine headache, low-back pain, and neck-pain. Compared with subjects who used analgesic appropriately, overusers were10.3 times more likely to report chronic migraine.

"This is the first study reporting the age and gender distribution of chronic headache associated with analgesic overuse in a general population," the researchers note. "The high number of individuals with analgesic overuse has important clinical implications, and physicians should be aware of the potential risk of analgesic overuse among those with chronic pain, especially among those with migraine."

Neurology 2004;62:1540-1544.