Surprised nobody has mentioned the fact that opioids are ototoxic. There's even been many threads regarding hearing damage/loss/tinnitus associated with opiate use. From what I recall reading, codeine and it's derivatives are the worst offenders. Overuse of APAP is thought to be a contributor, but not the sole cause as hearing loss has been associated with Methadone, Opium, Heroin, Tramadol, and possibly even Kratom.
There has been two threads in the past two weeks regarding tinnitus and hearing loss associated with kratom. I can attest to the tinnitus, but not hearing loss. I assume opiate related ototoxicity is worse with heavy abusers, but it's still a health problem that's under-discussed. Hearing loss aside, to say daily opioid use comes with no negative health effects rediculous.
Auditory sensitivity in opiate addicts with and without a history of noise exposure.
http://www.ncbi.nlm.nih.gov/pubmed/21959116
Review of Opioid-Associated Hearing Loss and Possible Mechanism of Opioid-Mediated Endothelin-1-Dependent Cochlear Vasoconstriction. (In full text)
http://scitechnol.com/review-opioid...learvasoconstriction-7aoU.php?article_id=1890
Hydrocodone Use and Sensorineural Hearing Loss Case Series
http://www.painphysicianjournal.com/linkout_vw.php?issn=1533-3159&vol=10&page=467
Profound hearing loss associated with hydrocodone/acetaminophen abuse.
http://www.ncbi.nlm.nih.gov/pubmed/10733182