To determine the impact of sumatriptan prophylaxis on acute mountain sickness (AMS) and altitude headache development within 24 hours of ascent, we designed a double-blind, randomized, clinical trial.


A prospective, double-blind, randomized, placebo-controlled trial was conducted in Tochal Mountain Hotel at an altitude of 3,500 meters above sea level during October 2006 to November 2006. A total of 102 Iranian adults were assigned to receive either sumatriptan succinate (50mg) or placebo within 1 hour of ascent. AMS incidence was measured by Lake Louise AMS score ≥ 3 with headache and one other symptom. Secondary outcome measures included severity of syndrome (Lake Louise scores ≥ 5), incidence of headache, and severity of headache.


Based on intention-to-treat analysis, AMS was more prevalent in placebo group (n = 23 [45.1%]) than sumatriptan group (n = 12 [23.5%]; p = 0.02). Headache also had a greater rate for placebo users (placebo vs sumatriptan group: 29 [56.9%] vs 17 [33.3%]; p = 0.02). No association was detected between sumatriptan prophylaxis and AMS or altitude headache severity.


Sumatriptan prophylaxis is effective to prevent AMS development. Furthermore, our findings confirm cerebral vasodilative and edematous mechanisms of AMS progression, whereas sumatriptan is a selective 5-hydroxytryptamine1 receptor subtype agonist and a selective cerebral vasoconstrictor as a result ( Ann Neurol 2007