Postmarketing surveillance of oral terbinafine in the UK: report of a large cohort study.

1. The safety profile of terbinafine, the first orally active allylamine, was monitored in the UK in a post-marketing setting. The study recruited 10,361 patients, a number which is approximately 5% of the population who received oral terbinafine in the UK during the period of the study. 2. Follow-up data were available on 9,879 patients. During the course of the study 14.5% patients reported medical events. 49% were thought to be possibly or probably related to terbinafine treatment. Seventy-four of the events (< 1%) were classified as 'serious' and of these only five were assessed as possibly or probably related to treatment. 3. Taste disturbance occurred in 0.6% of the patients and emerged as the only new adverse reaction probably attributable to terbinafine: this was significantly commoner in females and reversible on stopping treatment, with a median time to recovery of 42 days. 4. The study approach successfully combined hospital based dermatology outpatient and general practice centres. Source data verification was conducted on 13% of the cohort selected randomly. 5. Overall, the denominator-based description of the safety profile in actual practice shows terbinafine to be well-tolerated against a wide background of age and coexisting illness.