Antifungal Dosing for Tinea Infections

Dermatophyte (tinea) infections

§  Dermatophytes are filamentous fungi in the genera Trichophyton, Microsporum, and Epidermophyton.

§  Dermatophytes metabolize and subsist upon keratin in the skin, hair, and nails.

§  The major clinical subtypes of dermatophyte infections are:

	Location	Griseofulvin (microsize)	Fluconazole	Itraconazole
Tinea corporis	Body surfaces other than the feet, groin, face, scalp hair, or beard hair	500 mg OD-BD for 2-4 weeks1 or 4-6 weeks2	150-200 mg once weekly for 2-4 weeks3	200 mg OD for 1 week1 or 2 weeks2
Tinea cruris (jock itch)	Groin	500 mg OD-BD for 2-4 weeks1 or 4-6 weeks2	150-200 mg once weekly for 2-4 weeks3	200 mg OD for 1 week1 or 2 weeks2
Tinea pedis	Foot	500 mg BD for 4-8 weeks1 or 6-12 weeks2	150 mg once weekly for 2-6 weeks3	200 mg BD for 1 week1 or 200 mg OD for 2-4 weeks2
Tinea capitis	Scalp hair	(First line) 500 mg OD-BD for 4-6 weeks1 or 6-12 weeks2 or longer until fungal cultures are negative2	6 mg/kg/day (max. 400 mg/day) for 3-6 week 1 Or 8 mg/kg once weekly (max. 150 mg/week) for 8-12 weeks 4	200 mg OD for: 2 ·      Trichophyton: 2-4 weeks ·      Microsporum: 8-12 weeks Or 5 mg/kg/day (max. 400 mg/day) for 4-6 weeks 1
Tinea unguium (derma-tophyte onycho-mycosis) – Pulsed Therapy	Nail	-	150 mg2-300mg1,4 once weekly * Fingernail: 3-6 months 1,2,4 * Toenail: 6-12 months 1,2,4	(First line) 200 mg BD for 1 week per month 1,2 * Fingernail: 2 months * Toenail: 3 months
Tinea unguium (derma-tophyte onycho-mycosis) – Continuous Therapy	Nail	500 mg BD for 4-6 month or longer 2 * Fingernail: 6 months * Toenail: 12 months	-	(First line) 200 mg/day for:1 * Fingernail: 6 weeks * Toenail: 12 weeks

§  Based on NAG 2014: Treatment for tinea barbae (hair) is the same as tinea capitis.

§  Nystatin, an effective treatment for Candida infections, is NOT effective for dermatophytes.

§  Extra notes on griseofulvin:

o  Administer with a fatty meal to increase absorption

o  Laboratory evaluation prior to griseofulvin treatment is not necessary. However, if therapy is continued beyond eight weeks or repeated courses of griseofulvin are given, liver function tests and a complete blood count should be obtained to evaluate for hepatic or hematologic toxicity.

o  Teratogenic effects have been observed in animal reproduction studies. Griseofulvin crosses the placenta. Because adverse events have also been observed in humans (two cases of conjoined twins), use during pregnancy is contraindicated. Effective contraception should be used during therapy and for 1 month after therapy is discontinued in women of reproductive potential. Men should avoid fathering a child for at least 6 months after therapy.

Tinea versicolor

·      Tinea versicolor (ie, pityriasis versicolor) is a common superficial fungal infection. Patients with this disorder often present with hypopigmented, hyperpigmented, or erythematous macules on the trunk and proximal upper extremities.

·      Unlike other disorders utilizing the term tinea (eg, tinea pedis, tinea capitis), tinea versicolor is not a dermatophyte infection.

·      The causative organisms are saprophytic, lipid-dependent yeasts in the genus Malassezia (formerly known as Pityrosporum).

	Location	Griseofulvin (microsize)	Fluconazole	Itraconazole
Tinea versicolor	skin	NOT effective	If topical therapy failed: 300 mg once weekly for 2 week2 Or 400mg STAT 2	If topical therapy failed: 200 mg OD for 5-7 days2 Or 200 mg OD for 7 days (recurrent cases)2 Or 400mg STAT 2,4

References:

1. UptoDate on Tinea topics [Accessed on 28 Nov 2018]
2. National Antibiotic Guideline 2014
3. UptoDate: Fluconazole: Drug information [Accessed on 28 Nov 2018]
4. Sanford Guide to Antimicrobial Therapy [Apps: Last Updated on 24 Nov 2018]