Name: Amphotericin B (Fungizone)
Class: Antifungal (Polyene)
Mech.: Assoc. w/ergosterol in fungal membrane ® 4-5 Å pores. Fungistatic at low conc. Fungicidal at high conc.
Absorption: Insoluble in water. Colloidal preparation injected IV. Not absorbed orally, IM, or after bladder irrigation. Used topically.
Distribution: Bound to cholesterol and lipoprotiens. Poor CSF. Intrathecal may be necessary to treat meningitis.
Excretion, t½: Excreted very slowly as inactive metabolite by kidney.
Toxicity/S.E.s: Nephrotoxicity (80%) requires hospitalization for administration. Chills (50%), fever, nausea, vomiting, diarrhea, headache, phlebitis, suppression of RBC synth. IT ® headache, radiculitis, paresis, paresthesias, visual impairment.
Utility: 1° drug used against serious systemic infections. DOC for 1° amebic meningoencephalitis caused by Naegleria. Alt. for American cutaneous or mucocutaneous leishmoniasis. Weekly injections for chronic suppression of Histoplasmosis in AIDS patients.
Special Features: No problem w/resistance development. Increases fungal permeability to other agents.