Background: Benign Paroxysmal Positional Vertigo (BPPV) is the most common cause of peripheral vertigo in adults. Reason of this type of vertigo is movement of otoliths in semicircular canals (especially posterior). Main treatments for BPPV are antivertiginous drugs and maneuvertherapy. The purpose of this study is to determine the efficacy of Dimenhydrinate after maneuvertherapy of Epley on duration, number of vertigo attacks and duration of dizziness after each vertigo attack in patients with Posterior canal BPPV.

  Methods: one hundred forty eight patients with posterior Canal BPPV were evaluated in a randomized clinical trial in 2008 _2009.Maneuvertherapy of Epley were done for all patients. They were divided into two groups: Dimenhydrinate group (75) and Placebo group (73) and drug prescribed for 2 weeks. Patients were followed up after treatment for duration of vertigo (days), number of vertigo attacks and duration of dizziness after each vertigo attack (minute). Data were analyzed with statistical software SPSS 11/5 and comparison of means were done with T test and relationship between qualitative variables with X² square.

  Results: Mean duration of recovery from vertigo attacks were 3/2±2/9 days in Dimenhydrinate and 3/8± 3/3 in Placebo groups, mean number of vertigo attacks after treatment were 2±0/7 in Dimenhydrinate and 2/2 ±1 in placebo groups and Mean duration of dizziness after each vertigo attack was 32/75± 2/07 minutes in Dimenhydrinate and 39 ± 3/55 minutes in placebo groups with no statistically difference (P<0/05).

  Conclusion: Epley maneuvertherapy is an effective treatment for Posterior canal BPPV and adding Dimenhydrinate does not increase its effectiveness.