an antifungal medication is a pharmaceutical fungicide used to treat and prevent mycoses such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as cryptococcal meningitis, and others. such drugs are usually obtained by a doctor's prescription, but a few are available over-the-counter. ==classes== ===polyene antifungals===  a polyene is a molecule with multiple conjugated double bonds. a polyene antifungal is a macrocyclic polyene with a heavily hydroxylated region on the ring opposite the conjugated system. this makes polyene antifungals amphiphilic. the polyene antimycotics bind with sterols in the fungal cell membrane, principally ergosterol. this changes the transition temperature (tg) of the cell membrane, thereby placing the membrane in a less fluid, more crystalline state. (in ordinary circumstances membrane sterols increase the packing of the phospholipid bilayer making the plasma membrane more dense.) as a result, the cell's contents including monovalent ions (k+, na+, h+, and cl-), small organic molecules leak and this is regarded one of the primary ways cell dies.baginski m, czub b. "amphotericin b and its new derivatives." current drug metabolism. 2009 jun;10(5) : 459â69 animal cells contain cholesterol instead of ergosterol and so they are much less susceptible. however, at therapeutic doses, some amphotericin b may bind to animal membrane cholesterol, increasing the risk of human toxicity. amphotericin b is nephrotoxic when given intravenously. as a polyene's hydrophobic chain is shortened, its sterol binding activity is increased. therefore, further reduction of the hydrophobic chain may result in it binding to cholesterol, making it toxic to animals. * amphotericin b * candicidin * filipin â 35 carbons, binds to cholesterol (toxic) * hamycin * natamycin â 33 carbons, binds well to ergosterol * nystatin * rimocidin ===imidazole, triazole, and thiazole antifungals=== azole antifungal drugs (except for abafungin) inhibit the enzyme lanosterol 14 Î±-demethylase; the enzyme necessary to convert lanosterol to ergosterol. depletion of ergosterol in fungal membrane disrupts the structure and many functions of fungal membrane leading to inhibition of fungal growth.sheehan d., hitchcock c, sibley c. current and emerging azole antifungal agents ====imidazoles====  * bifonazole * butoconazole * clotrimazole * econazole * fenticonazole * isoconazole * ketoconazole * luliconazole * miconazole * omoconazole * oxiconazole * sertaconazole * sulconazole * 
Antifungals Fungicides