There is no established evidence that prednisone works for noise induced hearing loss right? Btw it is also on the ototoxic list of medications and has tinnitus as a side effect.
J Otolaryngol Head Neck Surg. 2017; 46: 41. Published online 2017 May 23
Current insights in noise-induced hearing loss: a literature review of the underlying mechanism, pathophysiology, asymmetry, and management options
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Anti-inflammatory effects of corticosteroids to reduce noise induced trauma
Different types of pharmaceutical agents have been shown to reduce the risk of hearing loss secondary to acoustic trauma. Steroids, specifically intratympanic dexamethasone, may have a therapeutic beneficial effect on NIHL when given before [
162] or after [
163] acoustic trauma in animals. Although an effect is shown in a wide range of dosages, higher dosages appear to be associated with better hearing preservation [
162].
Different routes of delivery have been investigated in animals, including intratympanic, intraperitoneal and direct administration into the scala tympani, and all have demonstrated protective effects as evidenced by preserved hearing (15–20 dB lower hearing thresholds on auditory brainstem response (ABR) measurement and preserved cochlear architecture [
163,
164]. Each route of delivery may protect hearing at a different level; intratympanic administration appears to be more protective for the efferent terminal outer hair cells synapses, whereas intraperitoneal injections are more protective for the organ of Corti and stria vascularis architecture [
163]. Accordingly, there appears to be a synergistic benefit from the administration by both routes when treating NIHL [
165]. In human studies, it has been shown that after acoustic trauma, the administration of systemic with intratympanic steroid treatment results in better hearing outcomes than with systemic steroids alone [
165,
166]. Although there is some evidence for a protective effect of steroids in acute acoustic trauma, clearly it is not a long-term option for chronic occupational noise exposure considering the negative side effects of systemic long-term steroid usage.
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Eur Arch Otorhinolaryngol. 2016 Dec;273(12):4089-4101. Epub 2016 Feb 16.
Pharmacological agents used for treatment and prevention
in noise-induced hearing loss
Steroids
Interest in hormonal regulation of hearing physiology and sensitivity to noise has resulted in conservative strategies focusing on steroid hormones. The most studied steroids are dexamethasone and methylprednisolone. Administration route, timing and effective dose have all been investigated in various previous studies.
In a study performed by Wang et al., intraperitoneal injection of 1 mg/kg dexamethasone for five consecutive days in guinea pigs exposed to 115-dB SPL white band noise provided protection against NIHL, possibly by suppressing cochlear Hes1 expression via a glucocorticoid receptor-dependent mechanism [5]. In another study; 1-, 10-, 100- and 1000-ng/ml doses of dexamethasone were administered directly into the scala tympani of guinea pigs exposed to 120-dB SPL octave band noise on the fourth day of dexamethasone administration. Direct application of dexamethasone to the inner ear was reported to be effective in protecting against NIHL [6]. Arslan et al. [7] investigated the effect of dexamethasone in the treatment of NIHL in 26 rats. These were exposed to 115-dB SPL white noise for 3 h a day for 10 days. Dexamethasone was injected at 2 mg/kg for 7 days in the first hour after noise exposure. The final hearing threshold was 5 dB, a normal hearing level, in the treated group, which was significantly better than that in the non-treated group (22.5 dB nHL). The results showed that early initiation of dexamethasone therapy is effective in the treatment of NIHL.
Transtympanic administration of methylprednisolone is also effective in the treatment of NIHL. Ozdogan et al. [8] administered intratympanic methylprednisolone following noise exposure in 16 rats. They reported a decrease in the numbers of apoptotic cells in the outer and inner hair cells of the cochlea. They concluded that intratympanic methylprednisolone injection after acoustic trauma reduces outer hair cell loss. Tabuchi et al. [9] investigated the therapeutic time window of methylprednisolone in acoustic injury. Mice were exposed to 128-dB SPL for 4 h. The authors reported that when administered before or immediately after noise, methylprednisolone has a protective effect against acoustic injury. However, when administered 3 h after acoustic overexposure, no protective effect was observed. These findings suggest that the therapeutic time window of methylprednisolone is very short.
In contrast, studies have also reported that steroids have no otoprotective effect. Bas et al. [10] studied the effect of dexamethasone against NIHL in 32 rats exposed to 120-dB SPL noise for 4 h. The day before noise exposure and for a subsequent period of 14 days, the animals were administered dexamethasone. The authors reported that dexamethasone was not effective in protecting against NIHL. In another study performed by Takahashi et al. [11] guinea pigs were exposed to 110-, 115- or 120-dB SPL noise for 10 min. Methylprednisolone was given intraperitoneally for 7 days after noise exposure. The authors concluded that methylprednisolone is not effective in the treatment of acoustic trauma caused by exposure to 115- or 120-dB SPL, while it is effective in exposure to 110-dB SPL.
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