The influence of a melanin-binding drug on temporary threshold shift in humans.

To evaluate the hypothesis that inner-ear melanin protects the sensory cells against harmful noise, noise-induced temporary threshold shift (TTS) was measured in 12 subjects during treatment with the melanin-binding drug, chloroquine, and after cessation of the drug. It was demonstrated that susceptibility to TTS was increased by chloroquine. This increase was most pronounced in young individuals, with dark complexion, and diminished with age. The chloroquine-induced increase in TTS in individuals with a light complexion was small and seemed unaffected by age. It could be argued that patients should avoid noise exposure during treatment with melanin-binding drugs.