Intratympanic dexamethasone as initial therapy for idiopathic sudden sensorineural hearing loss: Clinical evaluation and laboratory investigation

Abstract Objective To evaluate the effect of intratympanic dexamethasone (ITD) as initial therapy for idiopathic sudden sensorineural hearing loss (ISSHL) as well as to determine the concentration-dependent time course distribution of dexamethasone in the inner ear. Methods Sixty-six patients with profound ISSHL were included. Twenty-two were treated with ITD and the rest as control. Audiograms were performed before the treatment and one month afterwards. In the animal study, dexamethasone of different concentrations (5, 10 and 20 mg/ml) was injected into the tympanums of three groups of SD rats (Groups A, B and C), their inner ears dissected free at various postinjection survival intervals. Immunofluorescence was applied to detect the locations of dexamethasone. Results The overall rate of good prognosis was 77.27% in ITD group, which was not significantly different from 81.82% in the control group. In the animal study, the higher local concentration and longer lasting period was found in Groups B and C. Conclusions ITD at 5 mg/ml did not add effect to systemic steroids in improving hearing outcomes in patients with ISSHL. An increase in dexamethasone concentration led to large variations in pharmacokinetics in animal study, showing potential value in optimizing the drug delivery protocols and improving the therapeutic results.