Antifungals

Medications used to treat fungal infections

Antifungal medications, also known as antimycotics, are a class of pharmaceutical agents used to treat and prevent infections caused by fungi. These medications act either by killing the fungal organisms (fungicidal) or by inhibiting their growth and reproduction (fungistatic). Antifungals are used to manage a wide spectrum of fungal infections, ranging from superficial skin conditions to serious systemic illnesses.

Uses

Antifungals are prescribed to treat a variety of fungal infections, collectively known as mycoses. These may include:

• Athlete's foot (tinea pedis)
• Ringworm (tinea corporis)
• Candidiasis (oral thrush, vaginal yeast infections)
• Onychomycosis (fungal nail infections)
• Cryptococcal meningitis
• Aspergillosis
• Histoplasmosis
• Blastomycosis
• Other opportunistic infections, particularly in immunocompromised individuals (e.g., those with HIV/AIDS, organ transplant recipients)

Classification

Antifungal drugs are classified based on their chemical structure and mechanism of action. Common classes include:

Polyenes

• Examples: Amphotericin B, Nystatin
• Mechanism: Binds to ergosterol in fungal cell membranes, causing leakage of cellular contents.

Azoles

• Subtypes: Imidazoles and Triazoles
• Examples: Fluconazole, Itraconazole, Ketoconazole, Clotrimazole
• Mechanism: Inhibit ergosterol synthesis by blocking the enzyme lanosterol 14α-demethylase.

Echinocandins

• Examples: Caspofungin, Micafungin, Anidulafungin
• Mechanism: Inhibit synthesis of β-(1,3)-D-glucan, a vital component of the fungal cell wall.

Allylamines

• Example: Terbinafine
• Mechanism: Inhibits squalene epoxidase, an enzyme involved in ergosterol synthesis.

Others

• Griseofulvin – disrupts fungal cell mitosis.
• Flucytosine – antimetabolite that interferes with fungal DNA synthesis.
• Tolnaftate, Ciclopirox – used for topical applications.

Routes of Administration

• Topical: Creams, ointments, powders (e.g., for athlete’s foot or ringworm)
• Oral: Tablets or capsules (e.g., for nail or systemic infections)
• Intravenous (IV): For severe systemic infections, particularly in hospitalized patients

Availability

While many antifungal agents require a prescription, some formulations—especially for mild skin conditions—are available as over-the-counter (OTC) medications. Examples of OTC antifungals include:

• Clotrimazole (e.g., for athlete’s foot, vaginal yeast infections)
• Miconazole
• Tolnaftate

Resistance

The rise of antifungal resistance poses a significant global health threat. Fungal pathogens, such as Candida auris and Aspergillus fumigatus, have developed resistance to commonly used antifungals, making infections more difficult to treat. Factors contributing to resistance include overuse or misuse of antifungal drugs, especially in agriculture and medicine.

Efforts to monitor and control antifungal resistance are being coordinated by public health agencies such as the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC).

Glossary of Antifungal Agents

This glossary provides a comprehensive list of antifungal agents, including their uses and chemical classifications.

Amorolfine – A topical antifungal that inhibits ergosterol synthesis, used for onychomycosis.

Amorolfine hydrochloride – The hydrochloride salt form of amorolfine.

Amphotericin B – A polyene antifungal used to treat systemic fungal infections like aspergillosis and cryptococcosis.

Anidulafungin – An echinocandin antifungal used for invasive candidiasis.

Bifonazole – An imidazole antifungal applied topically for dermatophytosis.

Bromochlorosalicylanilide – An older antifungal compound with limited current use.

Butenafine hydrochloride – A benzylamine antifungal used for tinea infections.

Butoconazole nitrate – A topical imidazole antifungal for vaginal candidiasis.

Calcium undecenoate – A salt of undecenoic acid with antifungal properties.

Candicidin – A polyene antifungal produced by Streptomyces griseus.

Caspofungin acetate – An echinocandin used intravenously for severe fungal infections.

Chlormidazole hydrochloride – An imidazole derivative used in topical antifungal preparations.

Chlorphenesin – A muscle relaxant with mild antifungal and antibacterial properties.

Ciclopirox – A broad-spectrum antifungal used in topical treatments for onychomycosis and seborrheic dermatitis.

Ciclopirox olamine – The ethanolamine salt of ciclopirox.

Climbazole – An imidazole antifungal found in anti-dandruff shampoos.

Clotrimazole – A widely used topical imidazole for various fungal infections.

Cloxiquine – An antifungal agent with additional antibacterial activity.

Croconazole hydrochloride – A topical antifungal of the imidazole group.

Eberconazole nitrate – A topical imidazole antifungal used to treat dermatophytosis and candidiasis.

Econazole – A broad-spectrum imidazole antifungal.

Econazole nitrate – The nitrate salt form of econazole.

Enilconazole – A veterinary antifungal used for treating animal mycoses.

Fenticlor – An antifungal and antibacterial agent.

Fenticonazole nitrate – A nitrate salt imidazole used for vaginal yeast infections.

Fluconazole – A triazole antifungal used orally or intravenously for systemic infections.

Flucytosine – An antimetabolite antifungal used in combination with amphotericin B.

Flutrimazole – A topical antifungal agent of the imidazole class.

Fosfluconazole – A phosphate prodrug of fluconazole for intravenous administration.

Griseofulvin – A fungistatic antibiotic derived from Penicillium, used for tinea infections.

Isoconazole – A topical antifungal for dermatophytosis and candidiasis.

Isoconazole nitrate – The nitrate salt form of isoconazole.

Itraconazole – A systemic triazole antifungal used for blastomycosis, histoplasmosis, and nail infections.

Ketoconazole – An older imidazole antifungal used topically and orally.

Lanoconazole – A topical antifungal of the imidazole group.

Liranaftate – A topical antifungal used in Japan for skin mycoses.

Mepartricin – An antifungal and antiprotozoal agent.

Micafungin sodium – An echinocandin used for invasive candidiasis.

Miconazole – A common topical imidazole antifungal.

Miconazole nitrate – The nitrate salt form of miconazole.

Naftifine hydrochloride – A topical allylamine antifungal used for tinea pedis.

Natamycin – A polyene antifungal used in food preservation and eye infections.

Neticonazole hydrochloride – A topical imidazole antifungal used in Japan.

Nystatin – A polyene antifungal effective against Candida infections.

Omoconazole nitrate – A topical imidazole antifungal.

Oxiconazole nitrate – A broad-spectrum topical imidazole.

Parconazole hydrochloride – An investigational imidazole antifungal.

Pentamycin – A macrolide antifungal used in gynecological infections.

Posaconazole – A systemic triazole antifungal used for aspergillosis and prophylaxis in immunocompromised patients.

Propionic acid – A naturally occurring antifungal fatty acid.

Calcium propionate – A food preservative with antifungal activity.

Sodium propionate – An antifungal preservative used in foods and cosmetics.

Pyrrolnitrin – An antifungal antibiotic derived from Pseudomonas.

Ravuconazole – A triazole antifungal under clinical development.

Sertaconazole nitrate – A broad-spectrum imidazole antifungal.

Siccanin – An older antifungal agent isolated from plant roots.

Sodium parachlorobenzoate – An antimicrobial compound with antifungal properties.

Sulconazole nitrate – A topical imidazole used to treat fungal skin infections.

Terbinafine – An oral and topical allylamine antifungal.

Terbinafine hydrochloride – The hydrochloride salt form of terbinafine.

Terconazole – A triazole antifungal used intravaginally.

Tioconazole – A topical antifungal used mainly for vaginal yeast infections.

Tolciclate – A topical antifungal used for dermatophyte infections.

Tolnaftate – A synthetic antifungal used for treating athlete's foot.

Triacetin – A plasticizer with mild antifungal properties.

Trimetrexate glucuronate – A folate analog with some antifungal activity.

Undecenoic acid – A fatty acid with fungistatic properties.

Zinc undecenoate – A salt of undecenoic acid with antifungal properties.

Voriconazole – A triazole antifungal used for invasive aspergillosis.