Topical antifungal

Topical antifungals are medications applied directly to the skin, nails, or mucous membranes to treat fungal infections. These infections can affect various parts of the body, including the skin, nails, and mucous membranes, and are caused by fungi such as dermatophytes, yeasts, and molds.

Mechanism of Action

Topical antifungals work by disrupting the cell membrane of the fungus, leading to cell death. Many of these medications target ergosterol, a key component of fungal cell membranes. By inhibiting the synthesis of ergosterol, these drugs compromise the integrity of the fungal cell membrane, causing leakage of cellular contents and ultimately cell death.

Structure of ergosterol, a target of many antifungal agents.

Common Types of Topical Antifungals

There are several classes of topical antifungal agents, each with different mechanisms of action:

• Azoles: This class includes drugs such as clotrimazole and miconazole. They inhibit the enzyme lanosterol 14_-demethylase, which is involved in the conversion of lanosterol to ergosterol.

• Allylamines: Examples include terbinafine and naftifine. These drugs inhibit squalene epoxidase, another enzyme involved in ergosterol synthesis.

• Polyenes: Nystatin is a common polyene antifungal that binds directly to ergosterol, forming pores in the fungal cell membrane.

Indications

Topical antifungals are used to treat a variety of fungal infections, including:

• Tinea infections: Such as athlete's foot (tinea pedis), jock itch (tinea cruris), and ringworm (tinea corporis).
• Candidiasis: Infections caused by Candida species, often affecting the skin and mucous membranes.
• Onychomycosis: Fungal infections of the nails.

Side Effects

Topical antifungals are generally well-tolerated, but some individuals may experience side effects such as:

• Local irritation
• Redness
• Itching
• Burning sensation

Related Pages

• Antifungal
• Fungal infection
• Ergosterol

References

• "Topical Antifungal Drugs." MedlinePlus, U.S. National Library of Medicine. [1]
• "Antifungal Agents." The Merck Manual Professional Edition.