Impairment through to loss of the sense of taste occurs in around 3% of patients taking the antifungal terbinafine (LAMISIL, generics; atd Arzneimitteldatenbank [Drug Database], as at May 2011; see a-t 2010; 41: 98; 1994; No. 11: 109; 1993; No. 1: 20). The Dutch pharmacovigilance centre Lareb now reports hearing impairment through to deafness on oral treatment in six patients (1). The adverse event is likely to be poorly recognized as a consequence of the treatment because it can have a long latency period. The hearing damage occurred after two days to six months and persisted permanently in two patients. A 64-year-old female patient continued taking terbinafine for another three months despite hearing loss of 30 to 60 dB. Her hearing had still not improved four and a half years after discontinuation of the antifungal agent. A 70-year-old male only noticed the hearing loss after taking terbinafine for six months. The treatment was continued for another six months. After cessation of the treatment, his hearing did not recover completely.

The WHO has 17 reports of reduced hearing capacity, 20 reports of deafness and 42 of tinnitus on terbinafine (1). The Federal Institute for Drugs and Medical Devices (BfArM) has 13 suspected reports of hearing defects, six of them report on tinnitus (2). On enquiry, the generics supplier Hexal declares five reports of impaired hearing with a time relationship to terbinafine - hardness of hearing in three cases and tinnitus in two cases (3).

Although hearing problems have been reported with terbinafine for 15 years (a-t 1997; No. 5: 58), there is hitherto no reference to this in the Summary of Product Characteristics (SPCs) issued by the manufacturer of the original product (LAMISIL (4)) or generics manufacturers (e.g. TERBINAFIN HEXAL (5)).

1

Lareb: Oral terbinafine and hearing disorders, April 2011 http://www.lareb.nl/documents/kwb_2011_1_terbi.pdf

2

BfArM: Letter, dated 25 May 2011

3

Hexal: Letter, dated 23 May 2011

4

Novartis Pharma: SPC LAMISIL tablets, as at June 2008

5

Hexal: SPC TERBINAFIN HEXAL, as at March 2011