Anti fungal drugs are medicines that are used for curing fungal diseases such as candidiasis/thrush, athlete’s foot and ringworm and systemic infections like cryptococcal meningitis. They are used in anti dandruff shampoos to inhibit growth of Malassezia furfur (earlier called Pityrosporum ovale) that cause Tinea Versicolor and seborrhoeic dermatitis.

Unlike bacteria, fungi cells are similar to human cells at the molecular level as both are Eukaryotes. However, some differences do exist. Antifungal medications exploit these differences to kill the fungus organism without harming the human host. Let’s check out some effective antifungal drugs.

Polygene

Natamycin (33 carbons), Rimocidin, Filipin (35 carbons), Nystatin, Amphotericin B and Candicin are some Polyene Antifungals (macro cyclic polyene). A Polyene molecule is characterized by manifold conjugated double bonds. It is amohiohilic with a conjugated system and a hydroxylated ring on the opposite side. The Polyene antimycotics bind with sterols like ergo sterol to transform the fungal cell from fluid to a crystalline state. The conversion, effected through a temperature (Tg) change, causes leakage of the cells hydrophilic contents and it dies.
Polyene antifungals (Example Filipin) become toxic for animals when a polyene’s hydrophobic chain gets reduced and its sterol binding rates rises, causing it to bind with cholesterol.

Imidazole and Triazole

These drugs block fungal cell membrane synthesis and steroid synthesis. They prevent the conversion of lanosterol to ergo sterol by inhibiting the enzyme cytochrome P450 14alpha-demethylase.

Imidazole drugs include Miconazole (Miconazole Nitrate), Ketoconazole, Clotrimazole marketed as Lotrimin/Lotrimin AF (and Canesten in the UK), Econazole, Bifonazole, Butoconazole, Fenticonazole, Isoconazole, Oxiconazole, Sertaconazole (marketed as Ertaczo in North America), Sulconazole and Tioconazole.

The new nontoxic Triazole drugs include Fluconazole, Itraconazole, Isavuconazole, Ravuconazole, Posaconazole, Voriconazole, and Teraconazole.

Allylamines

Allylamines like Terbinafine (marketed as Lamisil in North America, UK, Germany, Australia and the Netherlands), Amorolfine, Naftifine (Naftin in North America) and Butenafine (Lotrimin Ultra) kill fungal cells by inhibiting an enzyme-squalene epoxidase, and ergosterol synthesis.

Echinocandins

Echinocandins like Anidulafungin, Caspofungin and Micafungin inhibit the enzyme 1,3 Beta Gulcan synthase to stop formation of glucan in the fungal cell wall, killing it.

Other Antifungal Drugs

Benzoic acid when combined with Whitfield’s Ointment (keratolytic agent) becomes an antifungal. Cicopirox (Ciclopirox olamine) is used to fight Tinea Versicolor. Tolnaftate is marketed under names like Desenex, Tinactin and Aftate. Flucytosine (5 Fluorocytosine) is an antimetabolite.Griseofulyin inhibits fungal mitosis by binding to polymerized microtubules. Haloprogin’s use has been discontinued because of its side effects. Undecylenic acid, an organic and unsaturated fatty acid obtained from castor oil, is an anti fungal, an anti viral and anti bacterial.

Alternatives to Antifungal drugs

Tea Tree Oil (ISO 4730 (“Oil of Melaleuca, Terpinen-4-ol type”), Citronella oil, Iodine (Lugols Solution), Lemon grass, orange oil, olive leaf, Palma Rosa oil, lemon myrtle, Neem Seed Oil, patchouli, Coconut Oil, Zinc diets, natural food containing zinc like chick peas and pumpkin seeds, Selenium diet supplements and Natural food containing Selenium like Brazil nuts are antifungal drug alternatives.

Antifungal drugs may cause life threatening side effects by destroying human cells along with fungal cells, when used improperly. Hence you should obtain them by a doctor’s prescription than over the counter.