Indian Journal of Dermatology: Published on July, 2017

Dermatophytosis are the most common fungal infections globally. According to the World Health Organization, the prevalence rate of superficial mycotic infection worldwide has been found to be 20%–25%. Hot and humid climate in the tropical and subtropical countries like Bangladesh makes dermatophytosis a very common superficial fungal infection.

Various antifungal agents both topical and systemic have been introduced into clinical practice for effectively treating dermatophytic conditions. The commonly used drugs include azoles (ketoconazole, itraconazole, fluconazole), allylamines (terbinafine), and griseofulvin.

Terbinafine is the orally available allylamine antifungal. Terbinafine is considered to be a first-line drug for the treatment of tinea corporis and cruris.

The drug has shown consistent efficacy against dermatophytes achieving more than 90% cure rates at a dose of 250 mg/day when administered for 2 weeks.

However, recently, clinical failure and relapses have been observed with terbinafine in patients with tinea infections with an increase in the incidence of terbinafine resistance.

The principle reasons may include low plasma concentration and incomplete cure which are very common following 2 weeks of therapy with 250 mg/day of terbinafine. The increased use, inappropriate prescribing and over the counter sale of antifungal agents has also added in the development of resistance to these drugs.

Hence, there was a need for a different treatment strategy while using terbinafine. Using higher dosages of terbinafine thus seems useful strategy in countering these problems.

TAKE HOME MESSAGE:

The authors conducted this survey with the aim of evaluating the efficacy and safety of terbinafine 500 mg given once daily in the treatment of patients with dermatophytosis.

Patients were divided into three groups depending on the duration of therapy:

Group A – terbinafine 500 mg for 2 weeks,

Group B – terbinafine 500 mg for 4 weeks, and

Group C – terbinafine 500 mg for 6 weeks.

Total 50 doctors completed the survey involving 440 patients. In this study following patients achieved clinical cure as:

87% patients in 2 weeks group (Group A)

92% patients in 4 weeks group (Group B) and

80% patients in 6 weeks group (Group C)

Adverse drug reactions of mild to moderate intensity related to terbinafine were seen in 57 patients.

What was known?

Terbinafine is considered to have good potency against tinea, but incomplete cure is common with current terbinafine 250 mg/day therapy.

What is new?

This study highlights the fact that incidence of terbinafine resistance is on the rise, terbinafine 250 mg/day for 2 weeks is not sufficient for treatment of dermatophytosis and use of higher dose terbinafine, i.e., terbianafine 500 mg for extended periods is associated with good efficacy and safety.

Conclusion

In this survey, terbinafine 500 mg given for 4 weeks was found to be most effective treatment strategy against superficial dermatophytosis.

The mycological cure rate was 83% (Group A), 90% (Group B), and 78% in Group C, at the end of follow-up period.

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