Drug treatments for subjective tinnitus: serendipitous discovery versus rational drug design.

Progress has been made in understanding the neural basis of subjective tinnitus (ST); however, this has not, as yet, translated into many new drug treatments. One reason for this is that realistic behavioral models of ST in animals have been developed only recently, and are still not widely used. Nonetheless, some significant pharmacological advances have been made. At present, there is evidence to support the efficacy of transtympanic gentamicin administration in the treatment of tinnitus associated with Meniere's disease; there is also some evidence to support the efficacy of intratympanic steroid and lidocaine application in the management of ST. Although benzodiazepines and anti-epileptic drugs appear to be effective in many cases of this condition, there is concern about their adverse side effect profile. Based on well-controlled clinical trials, vasodilators such as misoprostol, and histamine receptor ligands should be further investigated. Finally, given the evidence that ST is a form of sensory epilepsy, new antiepileptic drugs should be tested for potential efficacy as they are developed; such drugs may include novel N-methyl-D-aspartate receptor antagonists, as well as cannabinoids.