There are several antifungals in the market and it is difficult to understand how many more are needed since there are quite a few in the market. One major use is for treatment of Athelete’s foot.
Fungi contain cell wall made up of beta-1-3-glucan, other glucans and gylcoprotein. Below the cell wall there is a layer of chitin and below that cell membrane which is made up of phospholipid and ergosterol
There are three major classes of antifungal medications:
Polyenes – these bind of ergosterol and causes pores to develop in the cell membrane. This molecule has a hydrophobic and hydrophilic side that makes it form pores There are derived from streptomyces bacteria. Amphotericin B deoxycholate – Amphotericin – liposomal or lipid bicomplex. There is also Nystatin.These are broad spectrum active against Candida, Cryptococcus, Aspergilis and Mucoloci
Amphotericin is most toxic of antimicrobial compounds and mostly given topically. Usually Nephrotoxicity,
Azoles – inhibit lanosterol 14a demethylase and thus inhibits ergosterol synthesis
Most common: Fluconazole (first line of stable patients), Itraconazole (dimorphic fungi), Voriconazole (used for Aspergillus).
Less common : Posaconazole, Ketoconazole (usually has only for superficial activity and has anti-androgen activity), Clotrimazole, Miconazole – Both are used for superficial and mucocutaneous infections
They have hepatotoxicity and Fluconazole can cause alopecia
Echinocandins – inhibt the beta-1-3-glucan synthase. Caspofungin, Micfungin and Anidulafungin. It is fungicidal for Candida but fungistatic for Aspergillus. No major side effects and expensive to treat.
There are others: Griesofulvin was one of the early ones that bound to microtubules to prevent division.
Squalene oxidase inhibitor is Terbinafine (Squalene – Squalene epoxide – Loncosterol – Ergosterol)
Flucytosine – Cytosine deaminase converts flucytosine and can form 5FU. This can cause inhibition of replication and transcription.
