From the Townsend Letter for Doctors & Patients
Phytotherapy Review: Ginkgo and Ear Disorders
|Order this issue!|
Ginkgo biloba extract (GBE) is the most clinically-tested herbal
therapy for disorders involving the ear. However, results from clinical
trials have not always been consistent. This article reviews the available
clinical trials under the headings hearing loss, vestibular disorders and
tinnitus. Those trials for which outcomes for more than one of these disorders
were examined have been included under tinnitus.
In another trial, standardized Ginkgo extract (intravenous 200 mg/day for 9 days, followed by oral 160 mg/day for 6 weeks) was found to be superior to the drug piracetam for the treatment of sudden deafness (one-sided hearing loss).2 Median values for hearing thresholds in the range 250 to 3000 Hz were significantly lower with GBE treatment.
In a randomized comparative study published in 1994, 80 patients with idiopathic sudden hearing loss existing no longer than 10 days were treated with either standardized Ginkgo extract or naftidrofuryl (a vasodilator). After one week, 40% of patients in each group experienced a complete remission. After 3 weeks there was a significant borderline benefit for Ginkgo over naftidrofuryl. Ginkgo treatment was preferred due to a lack of side effects, unlike the naftidrofuryl.3
It appears that interest has been rekindled in this important but uncommon application for Ginkgo, with three clinical trials published in the past two years. One study conducted in India examined the value of GBE compared to a combined drug treatment for acquired sensorineural hearing loss in 52 patients.4 Probable etiologies included presbycusis (36.5%) followed by unknown causes (28.8%). Outcomes for GBE were better than the conventional treatment in responding patients. Response rates were similar between the two treatments.
In a relatively large trial involving 106 patients, the efficacies of two different doses of GBE for unilateral idiopathic sudden hearing loss were compared in a randomized double-blind design.5 The higher dosage of GBE appeared to accelerate and secure the recovery of patients, with a good chance for complete recovery. Positive results were observed after one week of treatment.
In a randomized, prospective, double-blind study involving 72 patients, the therapeutic efficacy of GBE (n=37) was compared to that of pentoxifylline (n=35) for the treatment of sudden deafness.6 The two treatments were equally well tolerated and showed a statistically significant equivalence either in improvement or in return to normal of the auditory thresholds in the two patient groups. Subjective assessment of the treatment (with regard to improvement in hearing and reduction in tinnitus) suggested that Ginkgo biloba extract was more beneficial than pentoxifylline.
A randomized, placebo-controlled, double-blind trial in 35 patients assessed the value of GBE at 160 mg/day for vestibular vertigo.8 The primary outcome measured was performance using posturography (assessment of body sway with eyes open or closed etc) and there was a statistically significant benefit from baseline observed for therapy with GBE, which was also superior to placebo.
A study conducted in three centers included 70 patients with vertigo of recent and idiopathic onset in a double-blind, placebo-controlled trial.9 The efficacy of GBE on both the frequency and duration of vertigo achieved statistical significance, with 47% of patients in the Ginkgo group free of symptoms at the end of the trial compared to 18% for the placebo group.
The most recent trial conducted in Poland compared GBE therapy plus physical therapy against physical therapy alone for the treatment of vestibular organ peripheral lesion syndrome in an open design.10 Patients in both groups improved, but improvement was clearer and faster, as assessed by dynamic posturography, for the group receiving GBE.
Tinnitus or Combined Syndromes
An early trial conducted in 1979 included 60 patients with hearing loss and/or vertigo and tinnitus.11 GBE (120 mg/day) was compared with nicergoline and found to be superior. Another early open design trial found good efficacy for GBE in patients with hearing impairment and tinnitus due to a variety of causes, mainly involving ischemia.12
Sixteen years ago, Meyer conducted a defining study on 103 patients which clearly established a reputation for Ginkgo in the treatment of tinnitus (deserved or otherwise).13 A randomized, double-blind, placebo-controlled trial was conducted with GBE including only patients with tinnitus of recent onset (less than one year). Improvement or cure was observed after an average of 70 days in patients treated with Ginkgo compared with 119 days in patients receiving placebo. Tinnitus which was of recent onset, unilateral and intermittent seemed to be particularly responsive to Ginkgo.
Soft laser therapy in combination with GBE for the treatment of tinnitus was found to be effective in one open trial14 and ineffective in another.15 In a double-blind, placebo-controlled trial involving 100 elderly patients (with at least four symptoms out of poor memory, anxiety, vertigo, tinnitus and headaches), therapy with GBE (112 mg/day) or placebo was assessed after 12 weeks.16 Improvement for tinnitus from baseline was 37% for the Ginkgo group versus 12% for the placebo group.
The 20 patients reporting a positive effect on persistent severe tinnitus in an open study involving 80 patients were included in a double-blind placebo-controlled crossover study.17 They received either Ginkgo extract (29.2 mg per day, 2 weeks) or placebo. The success of the treatment was based on patient preference (as there is no objective measurement) and on this basis Ginkgo did not demonstrate a significant effect. However, the dosage of Ginkgo extract used was probably subtherapeutic.
Again there has been recent interest in assessing the value of Ginkgo for tinnitus. A study published last year in the BMJ found no effect for GBE (150 mg/day) in treating tinnitus in a double-blind, placebo-controlled trial using mail questionnaires in 1121 healthy people with a comparatively stable condition.18
In contrast, a trial published this year involving 60 patients with chronic tinnitus found a positive result for GBE (200 mg/day by intravenous infusion for 10 days followed by oral therapy of 160 mg/day) compared with a placebo after 12 weeks of therapy.19 While results achieved statistical significance, the absolute difference between the two treatment groups was only moderate.
A systematic search of the literature identified 19 clinical trials (many early and not including the two above) investigating the effect of GBE on tinnitus.20 The results of eight controlled studies were found for the most part to show a statistically significant superiority of GBE over placebo or reference drugs. Tinnitus of recent onset had a better prognosis.
1. Dubreuil C. [Therapeutic trial in acute cochlear deafness. A comparative study of Ginkgo biloba extract and nicergoline]. Presse Med 1986; 15 (31): 1559-1561
2. Baschek V, Steinert W. In: Claussen CF, Kirtane MV, Schlitter K. (eds). Vertigo, Nausea, Tinnitus and Hypoacusia, in Metabolic Disorders. Elsevier, Amsterdam, 1988: pp 575-582.
3. Hoffmann F, Beck C, Schutz A. et al. [Ginkgo extract EGb 761 (tenobin)/HAES versus naftidrofuryl (Dusodril)/HAES. A randomized study of therapy of sudden deafness]. Laryngorhinootologie 1994; 73(3): 149-152
4. Kumar A, Raizada RM, Chaturvedi VN. Role of Ginkgo biloba extract in acquired sensorineural hearing loss. Indian J Otolaryngol Head Neck Surg 2000; 52(3): 212-219
5. Burschka MA, Hassan HA, Reineke T et al. Effect of treatment with Ginkgo biloba extract EGb 761 (oral) on unilateral idiopathic sudden hearing loss in a prospective randomized double-blind study of 106 outpatients. Eur Arch Otorhinolaryngol 2001; 258(5): 213-219
6. Reisser CH, Weidauer H. Ginkgo biloba extract Egb 761 or pentoxifylline for the treatment of sudden deafness: a randomized, reference-controlled, double-blind study. Acta Otolaryngol 2001; 121(5): 579-584
7. Schwerdtfeger F. Elektronystagmographisch und klinisch dokumentierte Therapie-erfahrungen mit rokan bei Schwindelsymptomatick. Therapiewoche 1981; 31: 8658-8667. In: DeFeudis FV. Ginkgo biloba Extract (EGb 761): Pharmacological Activities and Clinical Applications. Elsevier, Paris, 1991.
8. Hamann KF. Physikalische Therapie des vestibularen Schwindels in Verbindung mit GBE. Therapiewoche1985; 35: 4586-4590. In: DeFeudis FV. Ginkgo biloba Extract (EGb 761): Pharmacological Activities and Clinical Applications. Elsevier, Paris, 1991.
9. Haguenauer JP, Cantenot F, Koskas H et al. [Treatment of equilibrium disorders with Ginkgo biloba extract. A multicenter double-blind drug vs. placebo study]. Presse Med 1986; 15(31): 1569-1572
10. Orendorz-Fraczkowska K, Pospiech L, Gawron W. [Results of combined treatment for vestibular receptor impairment with physical therapy and Ginkgo biloba extract (Egb 761)]. Otolaryngol Pol 2002; 56(1): 83-88
11. Chesseboeuf L, Herard J, Trevin J. Etude comparative de deux vasoregulaterus dans les hypoacousies et les syndromes vertigineux. Med Nord Est 1979; 3; 534-539. In: DeFeudis FV. Ginkgo biloba Extract (EGb 761): Pharmacological Activities and Clinical Applications. Elsevier, Paris, 1991.
12. Artieres J. Effets therapeutiques du Tanakan sur les hypoacousies et les acouphenes. Lyon Mediterr Med 1978; 14: 2503-2515. In: DeFeudis FV. Ginkgo biloba Extract (EGb 761): Pharmacological Activities and Clinical Applications. Elsevier, Paris, 1991.
13. Meyer B. [Multicenter randomized double-blind drug vs. placebo study of the treatment of tinnitus with Ginkgo biloba extract]. Presse Med 1986; 15(31): 1562-1564
14. Plath P, Olivier J. Results of combined low-power laster therapy and extracts of Ginkgo biloba in cases of sensorineural hearing loss and tinnitus. Adv Otorhinolaryngol 1995; 49: 101-104
15. Partheniadis-Stumpf M, Maurer J, Mann W. [Soft laser therapy in combination with tebonin i.v. in tinnitus]. Laryngorhinootologie 1993; 72(1): 28-31
16. Vorberg G, Schenk N, Schmidt U. Herz Gefasse 1989; 9: 936-941
17. Holgers KM, Azelsson A, Pringle I. Ginkgo biloba extract for the treatment of tinnitus. Audiology 1994; 33(2): 85-92
18. Drew S, Davies E. Effectiveness of Ginkgo biloba in treating tinnitus: double blind, placebo controlled trial. BMJ 2001; 322(7278): 73
19. Morgenstern C, Biermann E. The efficacy of Ginkgo special extract EGb 761 in patients with tinnitus. Int J Clin Pharmacol Ther 2002; 40(5): 188-197
20. Holstein N. [Ginkgo special extract EGb 761 in tinnitus therapy. An overview of results of completed clinical trials]. Fortschr Med Orig 2001; 118(4): 157-164
our pre-2001 archives
for further information. Older issues of the printed magazine are also
indexed for your convenience.
© 1983-2002 Townsend Letter for Doctors & Patients
All rights reserved.
Web site by Sandy Hershelman Designs
|February 11, 2003|