Various drugs have a direct toxicity on the inner ear or on the auditory nerves, causing potentially irreversible deafness. The mechanisms of this deafness are poorly understood; it is uni- or bilateral and can occur gradually or suddenly. Sometimes it takes several months, years even, for it to be associated with the taking of medication.

Ototoxicity (drug toxicity affecting the ear) often depends on the drug dosage and the duration of exposure, and can continue after treatment has been halted. A perforated eardrum increases the risk of irreversible deafness when eardrops containing ototoxic substances are used.

Numerous drugs expose patients to hearing loss: anti-infectives such as antibiotics (especially aminoglycosides, vancomycin, macrolides, tetracyclines), antifungals, antimalarials, antivirals etc.  Anti-cancer drugs expose patients to lesions of the auditory nerves (cisplatin in particular, vinca-alkaloids and thalidomide). Various other drugs are also implicated: cardiovascular drugs, erectile dysfunction treatments, nonsteroidal anti-inflammatories, analgesics, drugs used in rheumatology, iron-binding drugs, immunosuppressants, drugs used in endocrinology, neuropsychotropic drugs, etc.

Different factors increase the risks of drug-related deafness: young or old age, dehydration, kidney function problems or the combination with another ototoxic drug. Informing patients enables them to watch out for the appearance of any warning symptoms, such as loss of hearing, vertigo or tinnitus (an abnormal auditory sensation which is not caused by an external sound).

©Prescrire 1 December 2014

"Drug-induced hearing loss" Prescrire Int 2014; 23 (155): 290-294. (Pdf, subscribers only).