ANTIFUNGAL AGENTS USED TO TREAT SYSTEMIC AND TOPICAL FUNGAL INFECTIONS
THERAPEUTIC USES | DOSAGE FORMS | MECHANISM OF ACTION | ELIMINATION | TOXIC EFFECTS/SIDE EFFECTS | OTHER INFORMATION | ||||
Amphotericin B | Aspergillosis, Cryptococcosis (meningial) | Suspension in deoxycholate, lipid complex, chlesteryl sulfate complex, liposomal, topical | Binds to ergosterol on the fungal membrane and disrupts the fungal membrane to form channels/leaks (especially with K+) and is fungistatic at low doses and fungicidal at high doses | Renal | Acute anaphylactic reaction, nephrotoxicity | 90% protein bound | |||
Nystatin | Candidiasis, vulvovaginal candidiasis, oropharyngeal candidiasis | Topical, lozenges, oral suspension, tablets | Binds to ergosterol on the fungal membrane and disrupts the fungal membrane to form channels/leaks (especially with K+) and is fungistatic at low doses and fungicidal at high doses | Renal | |||||
Flucytosine | Disseminated Candidiasis, Chromonycosis, Cryptococcosis | Capsules | Flucytosine is taken up into fungal cells and inhibits Thymidylate Synthase and prevents the production of dTMP, which is the rate limiting step to DNA synthesis | Renal (Reduce dose in renal impairment) | Bone marrow depression (Anemia, leukopenia, thrombocytopenia) | 2 - 4% protein bound | |||
Ketoconazole | 2nd line therapy for blastomycosis, candidiasis, coccidomycosis, histoplasmosis, paracoccidioidomycosis, psuedallescheriasis | Oral tablets, cream, shampoo | Inhibits 14-Alpha Demethylase enzyme and inhibits the demethylation of lanosterol. This inhibits the formation of ergosterol and causes leaky membranes of the fungal cells | Biliary | Hepatitis, liver toxicity, GI disturbances. Rare, dose dependent supression of steroid synthesis leading to gynecomastia and impotence in males and menstrual irregularities in females | Inhibits CYP3A4, Extensive hepatic metabolism, 99% protein bound. Sometimes used in Prostate Cancer since inhibits testosterone synthesis at high doses. | |||
Itraconazole | Histoplasmosis, blastomycosis, pseudallesheriasis, sporotrichosis | Capsules | Same As Ketoconazole | Biliary | Less inhibition of normal sterol biosynthesis and the related side-effects. Nausea, GI cramps, allergic rash, edema, hepatitis, hypokalemia, HTN | Better selection for 14-Alpha demethylase than ketoconazole. Extensive metabolism (oxidation at triazole ring and subsequent ring opening). Can use pulse therapy to treat onychomycosis. Potent inhibitor of CYP3A4 | |||
Fluconazole | Oropharyngeal candida, invasive candida, meningial cryptococcosis, vulvovaginal candida | IV solution, tablets | Same As Ketoconazole | Renal | GI disturbances, HA, occasional hepatotoxicity, Stevens-Johnson syndrome, thrombocytopenia | Less inhibition of CYP3A4 | |||
Voriconazole | Fluconazole-resistant candida | NOT YET APPROVED | Same as ketoconazole | Blurred vision, raised liver function enzymes | Undergoes hepatic metabolism | ||||
SCH-56592 (Posoconazole) | Aspergillus and resistant strains of candida | NOT YET APPROVED | Same as ketoconazole | Excellent pharmacokinetic profile and undergoing Phase II trials |