Does dimenhydrinate delay recovery of vestibular ocular reflex in acute unilateral vestibulopathy? A retrospective comparative study

Objectives: Acute unilateral vestibulopathy (UVP), also known as vestibular neuritis, is the third most common peripheral vestibulopathy. The acute autonomic symptoms of UVP can be controlled by the H1-receptor antagonist dimenhydrinate. Despite concerns about prolonged recovery from suppressed vestibular compensation when using dimenhydrinate, research is limited. Thus, we investigated the effect of dimenhydrinate on the recovery of UVP patients. Methods: We retrospectively analyzed patients who were diagnosed with UVP from April 2018 to April 2022. The patients were divided into those who were prescribed dimenhydrinate during admission and those who were not. Recovery from UVP was defined subjectively and objectively. Subjective recovery (SR) had occurred in a patient whose dizziness clearly subsided. Objective recovery (OR) was used when the video head-impulse test (VHIT) or rotary chair test (RCT) no longer indicated vestibular dysfunction. Results: Dimenhydrinate was prescribed to 15 patients (19.0%) during admission. The dimenhydrinate group had smaller proportions of SR and OR at 3 months after diagnosis of UVP. In terms of VHIT, the non-dimenhydrinate group had a greater increase in gain for the 3 months than the dimenhydrinate group in the semicircular canals when measured by the VHIT. The difference in gain between the two groups was significant at 0.16 Hz during follow-up RCT. Conclusion: These results suggest that dimenhydrinate should be carefully used in UVP patients as it may have a negative effect on vestibular compensation.