Analysis of the computer records of 100 general practices from the CompuFile Doctors Independent Network revealed 1492 patients receiving treatment for onychomycosis in the first 6 months of 1994 with terbinafine, tioconazole, amorolfine or griseofulvin.

These records indicated the average treatment time for each agent, number of general practitioner consultations and incidence of hospital referrals and minor surgery.

Applying standard costs to this resource consumption gave the direct costs for each of these four agents.

Published clinical and mycological cure rates allowed a cost per success to be calculated.

These were as follows : terbinafine (n=511) £258, amorolfine (n=315) £312, griseofulvin (n=196) £356 and tioconazole (n=470) £520.

Sensitivity analysis showed that terbinafine remained the most cost-effective option despite variations in resource costs.

The cost impact on a typical practice for switching from a less to a more cost-effective treatment is discussed.