The efficacy and tolerability of rizatriptan (MAXALT) and zolmitriptan (ZOMIG) were compared in a randomized, double-blind, double-dummy, stratified (on prior use of rizatriptan and/or zolmitriptan), placebo-controlled, single attack study in 766 patients. Rizatriptan tended to provide freedom from pain sooner than zolmitriptan (hazard ratio 1.26, P = 0.075), acting within 60 min following dosing. More patients were pain free at 2 h on rizatriptan than on zolmitriptan (43.2% vs. 35.6%, P=0.041), while headache relief at 2 h was similar (70.5% vs. 66.8%). At 2 h, fewer patients on rizatriptan had symptoms of photophobia (35.6% vs. 43.5%, P = 0.029) and nausea (25.2% vs. 32.5%, P=0.046), and more patients on rizatriptan had normal function (45.4% vs. 37.0%, P=0.025) than zolmitriptan. Headache recurred in 28% of patients taking rizatriptan, 29% taking zolmitriptan and 26% taking placebo. Both active treatments were effective compared to placebo and were well tolerated. The most common side-effects with rizatriptan were asthenia/fatigue, somnolence and dizziness, while the most common side-effects with zolmitriptan were asthenia/fatigue and dizziness.