End of the road for terbinafine? Results of a pragmatic prospective cohort study of 500 patients.

BACKGROUND: There is a general impression among dermatologists in India that terbinafine has been losing its effectiveness in dermatophytoses over the past few years, but there are no recent data to support this.

AIMS: To determine the effectiveness of terbinafine in tinea corporis, tinea cruris and tinea faciei with a pragmatic prospective cohort study.

METHODS: A sample size of 361 patients was calculated taking a 5% margin of error and a 95% confidence level. Five hundred patients with tinea corporis, tinea cruris and tinea faciei confirmed by potassium hydroxide microscopy received oral terbinafine (5mg/kg/day) and topical terbinafine 1% applied twice daily for 4 weeks. Patients were evaluated at 2 and 4 weeks. Cure was defined as total clearance of lesions and negative microscopy.

RESULTS: Patients who came for follow-up at 2 and 4 weeks numbered 357 and 362 respectively. Ten patients were cured at 2 weeks (cure rate 2%, 95% confidence interval 1.0-3.7%, intention-to-treat analysis) and 153 patients were cured at 4 weeks (cure rate 30.6%, 95% confidence interval 26.7-34.8%).

LIMITATIONS: Culture and antifungal susceptibility testing were not performed since this was a pragmatic study. There was also no follow up after completion of treatment to check for relapses, but the poor response makes this less relevant.

CONCLUSION: The effectiveness of terbinafine in dermatophytosis was abysmal in this study.