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- Ginkgo (Ginkgo biloba)
- Vertigo
- Safety and Efficacy
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Date:
10-15-2014 | HC# 091451-506
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Re: Ginkgo Comparable to Betahistine in Treating Vertigo and Has a Superior Safety Profile
Sokolova
L, Hoerr R, Mishchenko T. Treatment of vertigo: A randomized, double-blind trial
comparing efficacy and safety of Ginkgo
biloba extract EGb 761 and betahistine. Int
J Otolaryngol. 2014;2014:682439. doi: 10.1155/2014/682439.
Vertigo
(dizziness) associated with cerebrovascular disorders is most commonly treated
with drugs that improve cerebral blood flow. According to an international
survey, betahistine is the most frequently prescribed medication, followed by
piracetam, and then ginkgo (Ginkgo biloba).
Research suggests that impaired neuronal plasticity prevents compensation for
vestibular disturbances, and EGb 761® (manufactured by Dr. Willmar
Schwabe GmbH & Co. KG; Karlsruhe, Germany) has been shown to enhance
neuronal plasticity. The purpose of this randomized, controlled, double-blind, multi-center
study was to compare the efficacy and safety of ginkgo to that of betahistine
in the treatment of patients with vertigo.
Eligible
patients (n = 160, ≥ 45 years old) diagnosed according to the International Classification
of Diseases, 10th edition (ICD-10) with peripheral vertigo or vertiginous
syndrome not otherwise specified were enrolled in this study conducted at 10
outpatient hospital clinics in the Ukraine. Included patients had symptoms of
vertigo for ≥ 3 months, scored ≥ 3 on a 1-to-10 numeric analogue scale (NAS) of
vertigo severity at screening, and could respond to interview questions and
complete questionnaires in Russian or Ukrainian. Included females had a
negative pregnancy test and adequate birth control. Excluded patients had
specific vertiginous syndromes (e.g., Ménière's disease, Lermoyez syndrome, and
benign paroxysmal positional vertigo), vertigo due to specified somatic diseases
(except cerebrovascular disease), other severe disorders, contraindications for
ginkgo or betahistine, gastrointestinal disorders with uncertain absorption of
the active agents, or needed drugs that might interfere with efficacy
assessments.
Patients
were randomly assigned to receive either 240 mg/day ginkgo extract EGb 761 (60%
ginkgo leaf acetone extract standardized to contain 22-27% ginkgo flavonoids,
5-7% terpene lactones, 2.6-3.2% bilobalide, and ˂ 5 ppm ginkgolic acids) or 32
mg/day betahistine dihydrochloride for 12 weeks. Efficacy and safety were
evaluated at 4, 8, and 12 weeks. Efficacy was evaluated using: (1) the vertigo NAS;
(2) the short form of the Vertigo Symptom Scale, which assesses the frequency
and severity of vertigo within the last month; (3) the Sheehan Disability Scale,
which evaluates the extent psychological symptoms disrupt a patient's work,
social life, and family life; and (4) the Clinical Global Impressions (CGI)
Scale. Safety was monitored via measurement of vital signs, physical
examination, 12-lead electrocardiogram (ECG), and laboratory tests. There were
no significant differences between groups at baseline.
Both
groups improved compared to baseline on all measures. There were no significant
differences between groups on any measurement, although "numerically, the
improvements of patients receiving EGb 761 were slightly more pronounced on all
scales." On the CGI, physicians rated 79% of the patients receiving EGb
761 and 70% of the patients receiving betahistine as "much improved"
or "very much improved."
Blinded
review could not rule out a causal relationship for 6 adverse events (AEs) in 5
patients in the EGb 761 group and 18 AEs in 16 patients in the betahistine
group. In the EGb 761 group, both the total number of AEs and the number of
patients reporting AEs were lower compared to the betahistine group.
The
authors conclude that EGb 761 is at least as effective as betahistine, the
world's most frequently prescribed drug in the treatment of vertigo. Although
not statistically significant, numerically the EGb 761 group had more
pronounced improvements in all outcome measures. And in terms of safety and
tolerability, EGb 761 was superior to betahistine.
Despite
the fact that there were 80 patients per group, the study did not have
sufficient statistical power to prove equivalence between EGb 761 and betahistine.
The study had several other limitations: (1) there was no negative control (placebo
group) to provide an objective measure of the true effect size of both
treatments because it would be unethical to deny treatment to the placebo group;
(2) although assessments were conducted at 4 and 8 weeks, the interim data were
not reported so the elapsed time till onset of measurable improvements cannot
be compared; and (3) there was no follow-up to determine how long the therapeutic
benefit lasted after treatment discontinuation. Given comparable efficacy, the
latter 2 factors are important considerations when choosing a treatment. The
patients were not queried as to whether they would choose to continue the
treatment after the trial ended.
Nonetheless,
the data are encouraging because EGb 761 compared favorably to the most
frequently used drug for vertigo, it had fewer AEs in fewer patients, and might
be less expensive than betahistine [Note: Pharmacoeconomics were not discussed
in this report]. A larger, sufficiently powered clinical trial is needed to
prove equivalence and confirm ginkgo has a superior safety profile to
betahistine.
—Heather S. Oliff,
PhD
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