The reasons why macrolide antibiotics cause what is known as transient perceptive deafness is not well understood. To make matters worse, the exact site within the inner ear that is affected has been subject to much speculation.
Some investigators seem to think that the deafness is caused by damage to the stria vascularis, which is a layer of epithelium cells within the cochlea. It is thought the damage causes a change in the ionic potential within the cochlea, and this in turn causes the deafness.
Other workers suggest damage, effectively poisoning, of the nerve pathways within the inner ear.
The deafness and sometimes tinnitus is usually reversible from around one day to two months following cessation of the course, although sometimes patients with hepatic disorders take longer.
The risk of ototoxicity is also greater with the elderly and those with renal function problems.