Ototoxicity secondary to systemic aminoglycoside use is well known, and such therapy is usually accompanied by appropriate monitoring measures. It is now understood that there is a small risk (in the order of 1:1,000 to 1:10,000) of damage to the cochlea or vestibular labyrinth following the use of eardrops containing aminoglycoside, in circumstances where the drops may penetrate into the middle ear. This applies where there is a direct pathway to the middle ear due to a tympanic membrane perforation, patent grommet or in certain mastoid cavities where the middle ear is open.1 There is no risk from use of these drops in otitis externa where the tympanic membrane is intact.

Australian,2 American,3 British,4 and Canadian5 expert committees have recently promulgated guidelines on the use of potentially ototoxic drugs in patients whose ears are at risk, as above.

The Council of the New Zealand Society of Otolaryngology Head and Neck Surgery unanimously agreed on the statement shown in the box, which is based on the Australian and United States guidelines.

In essence, the Society recommends avoiding, wherever possible, the use of potentially ototoxic drops in patients with ears at risk.

However, potentially ototoxic agents may need to be used in certain circumstances—e.g. lack of therapeutic response to other agents, resistant organisms, non-availability, or non-affordability of non ototoxic agents. In these situations, potentially ototoxic drops may reasonably be used, but treatment should be limited to the period when the ear is actually discharging, and the principles of informed consent apply—i.e. the patient should understand the risks, alternative treatments, and requirement to report symptoms which might suggest damage to the inner ear. The Society does not believe routine audiometric monitoring is warranted by the risks of ototoxicity providing the treatment is of short duration (ideally no more than 14 days).

Careful and regular suction toilet to clear aural secretions and occasional use of systemic antibiotics play an important part in the management of inflammatory external/middle ear disease, but most cases will require administration of topical antibiotics, the effectiveness of which is increased by combination with a topical steroid. Unfortunately nearly all of the preparations available for this use contain aminoglycocides and the most effective non ototoxic alternative is very expensive. For this reason, the New Zealand Society of Otolaryngology Head and Neck Surgery is currently making a submission to PHARMAC recommending adequate subsidy of Ciprofloxacin/Hydrocortisone drops, which in many situations will be the most appropriate non ototoxic preparation to use.