Tinnitus treatment with piribedil guided by electrocochleography and acoustic otoemissions.
BACKGROUND
Tinnitus is a frequent disorder and very difficult to treat. Both animal studies and clinical observations suggest that dopaminergic substances might have potential for the treatment of tinnitus. Here, we investigated the dopamine agonist piribedil for the treatment of chronic tinnitus. In all participants, we performed audiometry, electrocochleography (ECoG), and otoacoustic emissions before treatment began.


OBJECTIVE
To assess the efficacy and safety of the dopaminergic drug piribedil for the treatment of tinnitus and to evaluate whether ECoG and acoustic otoemissions might be useful for predicting treatment response.


METHODS
Prospective randomized double-blind crossover study.


METHODS
One hundred patients with tinnitus were randomized into a double-blind, placebo-controlled, prospective crossover study. All patients underwent distortion product acoustic otoemissions with and without contralateral suppression and ECoG. Patients received 50 mg piribedil and placebo for 90 days each, separated by a 30-day washout period. Treatment effects were assessed by using the Tinnitus Handicap Inventory and a visual analog scale. Fifty-six patients completed the trial.


RESULTS
There was no significant improvement of Tinnitus Handicap Inventory and visual analog scale score after piribedil treatment as compared with placebo. However, results were characterized by high interindividual variability. Post hoc analysis of piribedil effects revealed that piribedil treatment responders differed from nonresponders by the occurrence of a double peak in the ECoG. In addition, normal distortion product acoustic otoemission suppression patterns indicated better treatment response with piribedil. The incidence of side effects during piribedil treatment was 23.3%, leading to interruption of treatment in all cases.


CONCLUSIONS
Piribedil is not superior to placebo in the treatment of tinnitus. Piribedil treatment responders differed from nonresponders by specific findings in the ECoG and in the distortion product acoustic otoacoustic emissions, suggesting a beneficial effect of piribedil in an electrophysiologically characterized tinnitus subgroup.
de Azevedo
Andréia Aparecida
AA
OTOSUL, Otorrinolaringologia Sul-Fluminense, Volta Redonda, Rio de Janeiro, Brazil. aaazevedo@otosul.com.br
Langguth
Berthold
B
de Oliveira
Patricia Mello
PM
Rodrigues Figueiredo
Ricardo
R
D000368:Aged; D001300:Audiometry, Evoked Response; D018592:Cross-Over Studies; D015259:Dopamine Agents / Q000008:administration & dosage* / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D010891:Piribedil / Q000008:administration & dosage* / Q000627:therapeutic use*; D014012:Tinnitus / Q000175:diagnosis / Q000188:drug therapy*
D015259:Dopamine Agents; D010891:Piribedil