REVIEW ARTICLESSteroid Nomenclature in Inner Ear TherapySalt, Alec N.∗; Plontke, Stefan K.† Author Information ∗Department of Otolaryngology, Washington University School of Medicine, St Louis, Missouri †Department of Otorhinolaryngology, Head and Neck Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany Address correspondence and reprint requests to Alec N. Salt, Ph.D., Department of Otolaryngology, Box 8115, 4560 Clayton Avenue, St. Louis, MO 63110; E-mail: [email protected] Sources of Support: Supported by the National Institutes on Deafness and Other Communication Disorders (NIDCD) of the National Institutes of Health (NIH) under award number R01 DC001368 (A.N.S.) and by Federal Ministry of Science and Research Germany (BMBF) grant number 01KG1427 (S.K.P.). Disclosure of Funding: NIH Financial Disclosure: A.N.S. is a paid consultant to Cochlear Corp., Sydney, Australia, Decibel Therapeutics Inc. Boston, USA, and Otonomy, Inc., San Diego, USA. S.K.P. is a paid consultant to AudioCure Pharma GmbH, Berlin, Germany and Boehringer Ingelheim, Ingelheim, Germany. Otology & Neurotology: July 2020 - Volume 41 - Issue 6 - p 722-726 doi: 10.1097/MAO.0000000000002624 Buy Metrics Abstract Local glucocorticosteroid (“steroid”) therapy is widely used to treat the inner ears of patients with Menière's disease, idiopathic sudden sensorineural hearing loss and in combination with cochlear implants. Applied steroids have included dexamethasone, methylprednisolone, and triamcinolone. In reality, however, this is often not true and the steroid forms commonly applied are dexamethasone-phosphate, methylprednisolone-hemisuccinate, or triamcinolone-acetonide. In each case, the additional component is not a counter-ion but is covalently bound to the molecule to increase aqueous solubility or potency. These drug forms are approved for intravenous or intramuscular delivery and are used “off-label” in the ear. When given systemically, the molecular form of the drug is of minor importance as the drugs are rapidly metabolized. In contrast, when administered intratympanically, the exact form of the drug has a major influence on entry into perilymph and elimination from perilymph, which in turn influences distribution along the cochlear scalae. Dexamethasone-phosphate has completely different molecular properties to dexamethasone and has different pharmacokinetic properties entering and leaving perilymph. Molecular properties and perilymph pharmacokinetics also differ markedly for triamcinolone and triamcinolone-acetonide. Methylprednisolone-hemisuccinate has completely different molecular properties to methylprednisolone. In the ear, different steroid forms cannot therefore be regarded as equivalent in terms of pharmacokinetics or efficacy. This presents a terminology problem, where in many cases the drug stated in publications may not be the form actually administered. The lack of precision in nomenclature is a serious problem for the inner ear drug delivery field and needs to be recognized. © 2020, Otology & Neurotology, Inc.