Triptans, like sumatriptan, are now an important cause of probable MOH, although these drugs cause headaches less frequently than do other medications, report Dr. Chelsea A. Meskunas from Princeton University in New Jersey and colleagues. Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are more important now than they were in the past, whereas ergotamine overuse is very rare.
Excessive use of anti-headache medication can lead to MOH. Although evidence suggests that frequent use of analgesics does not, per se, cause frequent headaches in everyone, in people who suffer migraines, overuse of painkillers is associated with an increase in the frequency of headaches, Meskunas and colleagues note. Frequent use of these medications may also render them less effective.
"Since many patients are overusing prescribed medications, public health initiatives should focus on educating doctors and patients about the importance of setting limits on the prescription and taking of acute medication, emphasizing that overuse of specific acute migraine medications may also be associated with probable MOH," they conclude.
Meskunas and colleagues reviewed the charts of 1,200 acute headache patients seen at one headache center during the years of 2005, 2000, 1995, and 1990. To gauge trends in MOH, the investigators selected 300 patients per year of interest.
The number of patients with a diagnosis of probable MOH remained "remarkably stable" over the study period, varying from 64 percent of all cases seen in the headache center in 1990 to 59 percent in 2005, the team reports.
The relative frequency of probable ergotamine overuse headache fell significantly, from 19 percent to 0 percent, whereas the frequency of probable overuse headache involving triptans, a newer class of drugs, rose significantly, from 0 percent to 22 percent.
The frequency of overuse headache due to simple analgesics increased from 8 percent to 32 percent, and for combinations of acute medications from 10 percent to 23 percent. The rate of opioid overuse headache declined, but the change was not significant.
"Acquiring up-to-date knowledge on the substances associated with probable MOH is a necessary step for planning strategies to address and relieve the burden of a sizeable number of headache patients," the authors write.