Clinical Question: Does ginkgo biloba prevent acute mountain sickness at high altitudes?

Setting: Outpatient (any)

Study Design: Randomized controlled trial (double-blinded)

Synopsis: Because the standard prophylaxis of acute mountain sickness, acetazolamide, causes side effects (e.g., a taste disturbance called the “champagne blues”), investigators have explored other treatment options. This study evaluated the effectiveness of ginkgo biloba alone or in combination with acetazolamide to treat patients with high-altitude acute mountain sickness.

The authors randomized 614 climbers who were beginning the ascent of Mount Everest from a base camp at 4,300 meters. Only 487 participants (79 percent) completed the study. Treatment allocation was concealed from the enrolling researcher. The climbers received acetazolamide in a dosage of 250 mg, ginkgo in a dosage of 120 mg (24 percent glycosides), both medications, or placebo twice a day. They received at least three doses before starting their ascent.

Using the Lake Louise questionnaire to evaluate symptoms, intention-to-treat analysis showed an incidence of acute mountain sick-ness in 12 percent of climbers taking acetazolamide, 35 percent taking ginkgo, 14 percent taking the combination, and 34 percent taking placebo (P < .05 for benefit with acetazolamide, alone or in combination, compared with placebo).

Severe sickness occurred in 18 percent of climbers treated with placebo or ginkgo, 3 percent of those treated with acetazolamide only, and 7 percent treated with the combination (significantly less for acetazolamide or the combination than for ginkgo or placebo). Headache occurred more frequently (31 percent) in patients receiving the combination than in those receiving acetazolamide alone (19 percent).

Bottom Line: Ginkgo biloba is ineffective in preventing acute mountain sickness. When used in conjunction with acetazolamide, ginkgo slightly increases the likelihood of headache, the most common symptom of acute mountain sickness (number needed to harm = nine). (Level of Evidence: 1b)