Topical antifungal drugs are used to treat fungal infections on the skin, scalp, nails, vagina or inside the mouth. These medications come as creams, gels, lotions, ointments, powders, shampoos, tinctures and sprays. Most antifungal drugs induce fungal cell death by destroying the cell wall of the fungus. These drugs inhibit the production of ergosterol, which is a fundamental component of the fungal cell membrane and wall.
Antifungal drugs are generally classified according to their chemical structures and their corresponding mechanism of actions. The four classes of topical antifungal drugs are azole antifungals, polyene antifungals, allylamine antifungals, and other antifungals. Azole antifungals inhibit the enzyme that converts lanosterol into ergosterol. Common examples of azole antifungals include clotrimazole, econazole, ketoconazole, miconazole, and tioconazole. The only polyene antifungal available topically is nystatin, which works by binding to ergosterol thus disrupting the integrity of the fungal cell membrane. Similar to azoles, allylamines disrupt the fungal cell wall synthesis through inhibition of the squalene epoxidase enzyme that converts squalene into ergosterol. Examples of allylamines antifungals comprise amorolfin, naftifine and terbinafine. The last group consists of antifungal drugs with a different mechanism of action than the other three classes. These drugs include benzoxaborole antifungals, ciclopirox olamine antifungals, thiocarbamate antifungals and undecylenic alkanolamide antifungals. Topical antifungal drugs may come with side effects such as itching and local irritation. They can also interact with food and different medications. Therefore, topical antifungals should be used with caution and with advice from medical professionals.