Clinical Briefs

With Comments from John La Puma, MD, FACP

Ginkgo biloba for Tinnitus

March 2001; Volume 4; 35

Source: Drew S, Davies E. Effectiveness of Ginkgo biloba in treating tinnitus: Double-blind, placebo-controlled trial. BMJ 2001; 322:73.

To determine whether ginkgo biloba is effective in treating tinnitus, we designed a double-blind, placebo-controlled trial using postal questionnaires and self-reported data.

We enrolled 1,121 healthy people aged between 18 and 70 years with tinnitus that was comparatively stable; 978 participants were matched (489 pairs). These pairs were given 12 weeks’ treatment with either 50 mg Ginkgo biloba extract LI 1370 tid or placebo. Our main outcome measures were participants’ assessment of tinnitus before, during, and after treatment. Questionnaires included items assessing perception of how loud tinnitus was and how troublesome it was. Changes in loudness were rated on a six-point scale. Changes in troublesomeness were rated on a five-point scale.

We found no significant differences in primary or secondary outcome measures between the groups. Thirty-four of 360 participants receiving active treatment reported that their tinnitus was less troublesome after 12 weeks of treatment compared with 35 of 360 participants who took placebo. We conclude that 50 mg Ginkgo biloba extract LI 1370 given three times daily for 12 weeks is no more effective than placebo in treating tinnitus.

Comment

Ringing in the ears is common enough to be troublesome to many people—it’s one of those annoyances that has no effective pharmacologic treatment, and about which doctors have little helpful to recommend.

So the idea that ginkgo leaf extract, probably effective in increasing cerebral blood flow and widely used for anything the least bit neurological, might be helpful was enough to have these University of Birmingham (UK) investigators give the Commission E standardized abstract to pairs of people with their ears buzzing, even without audiologic exams. The extract contained 25% flavonoids, 3% ginkgolides, and 5% bilobalides.

Alas, no go—10% response in both ginkgo and control groups.

Curiously, "one or more beneficial effects, such as improvements in general well-being, circulation, and hearing, were reported by 24/489 (4.9%) participants in the active treatment group and 11/489 (2.2%) in the placebo group. This difference was statistically significant (95% confidence interval 0.4%-4.9%)." No more is said about this finding. The study was funded by the British Tinnitus Association in conjunction with Lichtwer Pharma UK, manufacturer of the extract used in this study.

Recommendation

Ginkgo leaf extract cannot be recommended for tinnitus. Because it may increase the risk of bleeding with anticoagulant and antiplatelet drugs, it should not be co-administered with them.