Tuesday, March 07, 2006

Ginkgo effective in intermittent claudication

In this randomized, controlled, double-blind German study, Ginkgo biloba L. (Ginkgoaceae) was significantly superior to placebo in improving symptoms of intermittent claudication, a type of peripheral arterial disease which causes pain in the legs due to obstructed blood flow [Peters, 1998]. The severity of intermittent claudication is evaluated by measuring pain-free walking distance, an indication of how long patients can walk before experiencing symptoms. After six months of treatment, pain-free walking distance in the ginkgo group improved by almost 50 percent, compared to baseline measurements.

Results of the study lend further support to the positive results of earlier studies on the use of ginkgo in peripheral arterial disease, a number of which were reported in a meta-analysis of five placebo-controlled studies involving a total of 174 patients [Schneider, 1992]. Most of these studies have utilized EGb 761 (W. Schwabe, Karlsruhe, Germany), a concentrated ginkgo extract standardized to 24 percent ginkgo flavone glycosides and 6 percent terpene lactones.

For this 26-week study, 111 patients with confirmed peripheral occlusive arterial disease were randomized into two treatment groups. After a two-week run in placebo phase, subjects received treatment with either one tablet of standardized ginkgo extract three times a day, a total daily dose of 120 mg, or placebo. Results were assessed by comparing pain-free walking distance at the beginning of the trial with changes after eight, 16, and 24 weeks of treatment. The superior efficacy of ginkgo was statistically significant at all three evaluation points. Both treatment groups had increases in pain-free walking distance during the study, but after six months of treatment, the increase in pain-free walking distance in the ginkgo group was almost twice that of the placebo group. Increases in maximum walking distance were also significantly greater with ginkgo treatment. No side effects were reported in the ginkgo group; one patient in the placebo group complained of heartburn and gastric pain.