Excessive acute migraine medication use and migraine progression.

Long considered a chronic disorder with a stable course, recent research demonstrates that, in a subgroup, migraine progresses to chronic migraine. Among the risk factors for migraine progression, acute symptomatic medication overuse (SMO) is regarded as one of the most important. Though SMO and chronic migraine are associated, several questions remain unanswered. First, the causal path is controversial (SMO as a cause or consequence). Second, it is unclear if specific classes of medication, as well as critical doses of exposures, are necessary. Herein we review this topic in the light of recent conducted research. Although several caveats exist and the data should be taken with caution, important findings are as follows: 1) Opiates are associated with migraine progression; critical dose of exposure is around 8 days per month, and the effect is more pronounced in men. 2) Barbiturates are also associated with migraine progression. Critical dose of exposure is around 5 days per month and the effect is more pronounced in women. 3) Triptans induced migraine progression in those with high frequency of migraine at baseline (10-14 days per month), but not overall. 4) Anti-inflammatory medications were protective in those with <10 days of headache at baseline, and, as triptans, induced migraine progression in those with high frequency of headaches. Accordingly, specific classes of medications are associated with migraine progression, and high frequency of headaches seems to be a risk factor for chronic migraine regardless of medication exposure.