Antifungals & Antiprotozoals Overview

Antifungals & Antiprotozoals

• Antifungals target fungal infections.
• Different antifungals affect different cellular structures.
• Some antifungals target the nucleus, others the cell membrane.

Antifungal Examples (Affecting the Nucleus)

• Griseofulvin
• Flucytosine

Antifungal Examples (Affecting the Cell Membrane)

• Amphotericin B
• Imidazoles (Ketoconazole, Miconazole)
• Triazoles (Itraconazole, Fluconazole)

Dermatophytosis

• A fungal skin infection.
• An example is ringworm.
• Infections affect the skin, hair, and claws.
• Common in animals like dogs, cats, and horses.

Fungal Infections: Effectiveness

• Superficial mycoses: Fungal skin infections.
  • Example: Ringworm
• Systemic mycoses: Fungal infections within the body.
  • Example: Histoplasmosis, blastomycosis, aspergillosis.

Griseofulvin

• Used to treat dermatophytic fungal infections of skin, hair, and claws.
• Effective for dogs, cats, and horses.
• Fungistatic.
• Approved for systemic administration.
• Oral granules are absorbed better with fatty meals.

Griseofulvin (Continued)

• Fulvicin U/F is a form of Griseofulvin.
• Fungistatic, active against dermatophytes.
• Metabolized by the liver, eliminated by the kidney.
• Known teratogen in cats.
• Oral administration (PO).
• Fulvidex Otic Suspension is a combination product with dexamethasone.

Ancotil®

• Often used to treat Cryptococcus and Candida infections.
• Often combined with Amphotericin B and ketoconazole.
• Administered orally (PO).
• Potential side effects include GI disturbances, dose-dependent bone marrow depression, cutaneous eruptions, oral ulceration, and increased hepatic enzyme levels.

Amphotericin B

• A polyene macrolide effective against most fungal pathogens.
• Used for systemic mycoses.
• Administered as an intravenous (IV) suspension - rapid or slow bolus.
• Solution is diluted in 5% dextrose.
• Nephrotoxic; renal function must be monitored (dose-related toxicity)
• Toxicity may be reduced with mannitol or sodium loading.

Itraconazole

• Drug of choice for blastomycosis and cryptococcal meningitis.
• More expensive than ketoconazole.
• Available in various forms (tablets, oral solutions) for cats and humans.

Miconazole Nitrate

• Used to treat fungal infections in dogs and cats (e.g., Conofite Cream).
• Targets various fungal species (Microsporum canis, Microsporum gypseum, Trichophyton mentagrophytes).
• Applied topically.
• Dosage is based on lesion size (e.g., 1¼ ribbon per square inch of lesion).

Mycostatin, Nilstat, Panalog®

• Topical treatment only; very toxic systemically.
• Used to treat candidial infections of the skin, mucous membranes, & GI tract.
• Used to treat Microsporum canis ear infections.

Metronidazole (Flagyl®)

• An antibiotic in the nitroimidazole group.
• Used to treat obligate anaerobic bacteria (e.g., Trichomonas, Giardia, Amebae).
• Oral (PO) and other routes of administration.
• Penetrates the blood-brain barrier.
• Anti-inflammatory properties in the large intestine.
• Can be used to treat diarrhea.
• Drug interactions with phenobarbital, cimetidine, and cyclosporine.