acyclovir and Labyrinthitis

A subclinical viral labyrinthitis has been postulated in the literature to elicit idiopathic sudden sensorineural hearing loss (ISSHL). An etiologic role for the herpes family is assumed. Corticosteroids possess a limited beneficial effect on hearing recovery in ISSHL. In this study, we evaluated the therapeutic value of the antiherpetic drug acyclovir (Zovirax) on hearing recovery in 91 patients with ISSHL who received prednisolone in a prospective, randomized, double-blind, placebo-controlled, multicenter trial. The audiometric parameters included pure tone and speech audiometry. Subjective parameters studied included hearing recovery, a pressure sensation in the affected ear, vertigo, and tinnitus. A 1-year follow-up was obtained. Hearing recovery for the whole group averaged about 35 dB and was independent of the severity of the initial hearing loss or vestibular involvement. Speech audiometry improved from 49% to 75%. After 12 months, pressure sensation and vertigo decreased to 15.6% (acyclovir) and 10.3% (placebo) and 12.5% (acyclovir) and 10.7% (placebo), respectively. Tinnitus decreased slightly, to 46.9% (acyclovir) and 55.2% (placebo), in the same period (p > .05 for all parameters). We conclude that no beneficial effect from combining acyclovir with prednisolone can be established in patients with ISSHL.

Topics: Acyclovir; Adult; Anti-Inflammatory Agents; Antiviral Agents; Audiometry, Pure-Tone; Audiometry, Speech; Double-Blind Method; Drug Therapy, Combination; Female; Hearing Loss, Sensorineural; Hearing Loss, Sudden; Herpes Simplex; Humans; Labyrinthitis; Male; Prednisolone; Prospective Studies

Experimental herpes simplex virus type 1 (HSV-1) labyrinthitis provides a model of idiopathic sudden sensorineural hearing loss (ISSHL). Corticosteroids improve the prognosis for hearing recovery in ISSHL, but the effects of acyclovir are unknown. To establish the therapeutic efficacy of acyclovir (Zovirax) and prednisolone in experimental HSV-1 viral labyrinthitis, we induced HSV-1 labyrinthitis in 12 guinea pigs. Three animals received no treatment, 3 received prednisolone, 3 received acyclovir, and 3 received both. Four other animals served as controls, receiving culture medium only. Hearing, HSV-1 antibody titers, and cochlear damage were evaluated. The HSV-1 labyrinthitis caused hearing loss within 24 hours. Combination treatment consisting of prednisolone and acyclovir resulted in earlier hearing recovery and less extensive cochlear destruction compared to prednisolone or acyclovir as a monotherapy. The beneficial effect of this treatment modality remains to be demonstrated in ISSHL.

Topics: Acyclovir; Animals; Antiviral Agents; Cochlea; Drug Therapy, Combination; Glucocorticoids; Guinea Pigs; Hearing Loss, Sensorineural; Hearing Loss, Sudden; Herpes Simplex; Herpesvirus 1, Human; Labyrinthitis; Male; Prednisolone

Topics: Acyclovir; Herpes Simplex; Humans; Labyrinth Diseases; Labyrinthitis; Recurrence

The effectiveness of the antiviral agent ganciclovir (9-[1,3-dihydroxy-2-propoxymethyl]guanine) against guinea pig cytomegalovirus was tested in vitro in guinea pig embryonic fibroblasts and in vivo in an experimental guinea pig cytomegalovirus labyrinthitis model. In vitro, ganciclovir completely prevented guinea pig cytomegalovirus infection of guinea pig embryonic fibroblasts at concentrations above 32.6 micrograms/ml. In vivo, antibody-negative animals had an average 17-dB elevation in their auditory nerve compound action potential thresholds (P less than 0.01, t test) and showed signs bilaterally of guinea pig cytomegalovirus labyrinthitis 8 days after intrathecal inoculation of virus. Ganciclovir administration starting 1 day before inoculation prevented the development of both cochlear histopathologic change and hearing loss. Guinea pig cytomegalovirus meningitis was observed in both the drug-treated and untreated groups. High-pressure liquid chromatography confirmed the presence of ganciclovir in the serum, perilymph, and cerebrospinal fluid of the drug recipients. Prophylactic ganciclovir thus can protect the cochlea from the histopathologic changes and hearing loss normally associated with experimental guinea pig cytomegalovirus labyrinthitis.

Topics: Acoustic Stimulation; Acyclovir; Animals; Antiviral Agents; Cells, Cultured; Cochlea; Cytomegalovirus Infections; Female; Ganciclovir; Guinea Pigs; Labyrinth Diseases; Labyrinthitis; Sensory Thresholds; Vestibulocochlear Nerve