Correlation of plasma levels of itraconazole with treatment response at 4 weeks in chronic dermatophytosis: Results of a randomised controlled trial.

BACKGROUND

Itraconazole in varying doses and duration is being frequently used for the management of dermatophytosis. There is a scarcity of studies on the bioavailability of various itraconazole brands available in the market.

AIMS AND

OBJECTIVES

The aim of this study was to determine the plasma concentration of itraconazole of various brands and its correlation with clinical efficacy in chronic dermatophytosis.

MATERIALS AND

METHODS

One hundred patients with chronic dermatophytosis with age >18 years were studied at the outpatient clinic of our tertiary care hospital. Plasma itraconazole level was estimated on Week 2 and Week 4 after randomly dividing the patients into Groups A, B and C who received cap itraconazole 100 mg twice a day of innovator, multinational and local generic brands, respectively, for 4 weeks. Both efficacy (cure, partial cure or no cure), safety and recurrence were compared between the three groups.

RESULTS

At 4 weeks, number of patients classified as 'cured' were 10/26 (38.4%) in Group A, 5/22 in Group B (22.7%) and 3/21 (14.2%) in Group C (p = .002). Mycological cure rates at Week 4 in Groups A, B and C were 21 (80.8%), 17 (81.0%) and 5 (26.3%), respectively (p = .006). Plasma levels of itraconazole were comparable between the three groups at Week 2 and Week 4. No statistically significant correlation was found between itraconazole levels and treatment response in any of the groups at 4 weeks. Incidence of adverse effects and recurrence rates was also similar among the three groups.

CONCLUSION

Cure rates for chronic dermatophytosis were poor with all three itraconazole brands at 4 weeks of treatment. Higher cure rates were obtained with innovator drug as compared to multinational and local generic brands at 4 weeks. Plasma levels of the three drugs were however similar, indicating that factors other than serum bioavailability are at play in determining response of chronic dermatophyte infections to oral itraconazole.