Source: DGNews  |  Posted 2 years ago

By Crina Frincu-Mallos, PhD

BALTIMORE, Md -- October 20, 2009 -- Acetazolamide is safe and effective in the treatment of patients with episodic vertigo, according to a study presented at the American Neurological Association (ANA) 134th Annual Meeting.

Acetazolamide has been used to treat the intraocular pressure associated with glaucoma, and, more recently, for the treatment of vertigo in patients with familial episodic ataxia, explained Michelle L. Bell, PsyD, Mount Sinai School of Medicine, New York, New York, who presented the study here on October 12.

“We tested the hypothesis that acetazolamide would reduce the frequency of vertigo attacks in patients with episodic vertigo,” noted Dr. Bell. She and her colleagues aimed to assess the efficacy of the therapy in these patients. They reviewed all charts of patients who were treated at Mount Sinai for episodic vertigo between 1996 and 2008.

The resulting retrospective analysis identified 68 patients who received acetazolamide. “Patients whose symptoms met the criteria for labyrinthitis, Ménière’s disease, or benign positional vertigo were excluded,” Dr. Bell indicated.

The remaining 42 patients with episodic vertigo were contacted and asked to complete an 11-question telephone survey. Of the 27 subjects who took the drug for more than 1 week, 25 subjects participated in the survey.

The mean age of the 25 subjects analysed was 46.4 years (range, 20 to 71 years); 19 were female. The episodes of vertigo occurred at least 5 times per month, and some symptoms could last for 17 hours.

The survey addressed changes in frequency, intensity, and duration of the vertigo attacks, side effects of acetazolamide therapy, as well as changes in dose from that which was initially prescribed.

The survey data was correlated with the electronystagmography (ENG) data, used to assess eye movements (both voluntary and involuntary), and thereby evaluating the acoustic nerve, which aids with hearing and balance.

In 19 of the 25 patients surveyed, a 250-mg dose of acetazolamide given 3 times daily reduced vertigo and, in fact, totally eradicated it in 12 patients. Acetazolamide elicited this effect within days from the initiation of the treatment; however, 78% of responders (n = 15) were still on acetazolamide at the time of the survey.

The ENG data did not differ between patients who responded to acetazolamide therapy and those who did not respond. The investigators noted that most responders had elements of inner-ear pathology, as shown in their ENG data; acetazolamide has been known to affect the inner ear. “This effect has been thought to be secondary to the high concentration of carbonic anhydrase in the cochlea and endolymphatic sac,” Dr. Bell noted.

Side effects associated with the acetazolamide in this study included tingling of fingers, tongue, and toes, as well as fatigue. The investigators pointed out that none of the patients developed a skin rash, which is sometimes associated with the drug.

The investigators concluded that the response to acetazolamide in patients with episodic vertigo suggests that there might be pathological mechanisms similar to those involved in Ménière’s disease, as some of those patients also respond to acetazolamide.

Presentation title: Acetazolamide-Responsive Episodic Vertigo. Abstract M-100