Among individuals with episodic migraine, the influence of excessive acute medication use on the development of chronic migraine depends upon within-person characteristics (eg, headache frequency), class of drug, and frequency of medication use. Available data suggest that opioids induce migraine chronification (progression), and the effect is dose dependent (critical dose around 8 days of exposure per month) and more pronounced in men. Barbiturates also induce migraine progression, and the effect is dose dependent (critical dose around 5 days of exposure per month) and more pronounced in women. Triptans induce migraine progression only in those with high migraine frequency at baseline (10-14 days per month), but not overall. NSAIDs protect against migraine progression unless individuals have 10 or more headache days per month (when they become inducers, rather than protective). Finally, caffeine-containing over-the-counter products increase risk of progression. While we await randomized trials, these findings should inform the choice of acute migraine treatments with the goal of reducing the risk of migraine progression to chronic migraine.