A potentially addictive, narcotic painkiller. Although no studies have conclusively proven it, long term and excessive abuse of Vicodin may lead to sudden and complete hearing loss, as has been reported in the Los Angeles Times.
A friend of mine used Vicodin for years after becoming addicted to it when it was presecribed to her for back surgery aftercare. Within the space of a month, her hearing went from near perfect to zero. Did the Vicodin cause this? I honestly don't know.
Fortunately, doctors were able to restore most of her hearing by giving her cochlear implants. In the inner ear, there are a series of hairs; each hair is stimulated by a specific frequency of vibration, and when stimulated, the hair triggers an impulse in a corresponding nerve. It is these impulses that allow the brain to perceive sound. Apparently, in those cases of hearing loss where Vicodin abuse is the suspected cause, these hairs have been deformed or deteriorated and no longer trigger the correct nerve impulses. Cochlear implants are devices that replace the functions of these hairs and do trigger the correct nerve impulses by digitizing incoming sound.