Topical antifungal drugs are applied externally on the body in the form of cream, ointment, gel, lotion, spray, shampoo or powder. These are used to treat fungal infections on skin, hair, nails, vagina and inside the mouth. The benefit of topical application is that it has minimal adverse effects on the body as well as maximizing drug concentration in tissues with limited blood perfusion. They may cause itching or local irritation as a side effect.
Allylamines
Terbinafine, butenafine and naftifine are long-acting topical antifungal, applied once a day. It works by inhibiting the squalene epoxidase enzyme involved in ergosterol synthesis pathway.
Azoles
It acts by inhibiting 14-α-demethylase enzyme involved in ergosterol synthesis pathway. They are most widely used antifungal group. Azoles have additional antibacterial activity against gram-negative and anti-inflammatory activity by inhibiting chemotaxis.
- Econazole
- Miconazole
- Clotrimazole
- Ketoconazole
Newer azoles
- Luliconazole – long acting, required single dose daily
- Sertaconazole – additional anti-pruritic activity and inhibit IL-2,4 and TNF-α
- Eberconazole – inhibit LOX and COX enzyme as additional activity
- Efinaconazole
Amorolfine
It interferes ergosterol biosynthesis by inhibiting delta 14 reduction of ignosterol. Accumulation of ignosterol leads to fungicidal action. It is available as nail lacquer for the treatment of onychomycosis. It is also used for vaginal candidiasis and dermatophytosis.
Benzoic acid
it exhibits antifungal as well as antibacterial properties in slightly acidic medium. eradication of the fungus needs prolonged application till infected keratin is totally shed. On hyperkeratotic lesions, it is used in combination with salicylic acid (as Whitfield’s ointment: benzoic acid 6%, salicylic acid 3%). Through its keratolytic effect, salicylic acid helps to remove infected tissue and facilitates the penetration of benzoic acid into the lesion.
Ciclopirox
Ciclopirox is a hydroxypyridone that inhibits metal-dependent enzymes (cytochromes, catalase, and peroxidase) by chelating the trivalent cations Fe3+ or Al3+, which disrupts cellular processes including the mitochondrial electron transport chain. It is a broad-spectrum antifungal agent with additional antibacterial (against gram-negative) and anti-inflammatory activities (as decreases oxidative stress). It is available as ciclopirox olamine nail lacquer (paint).
Tavaborole
It works by inhibiting the key fungal enzyme needed for protein synthesis, leucyl-tRNA synthase (by establishing a boron-based bond). It is available as nail paint for the treatment of onychomycosis.
Undecylenic acid
It is mainly a fungistatic drug, generally used as its zinc salt. It is available as ointment, cream, powder, soap and liquid. It is used in the treatment of tinea pedis, tinea cruris and other dermatophytosis.