Drugs & Medication

An antifungal drug is medication used to treat fungal infections such as athlete's foot, ringworm and candidiasis (thrush), as well as serious systemic infections like cryptococcal meningitis. Such drugs can be either prescription drugs or OTC drugs.

Contents 1 List of antifungal drugs 1.1 Polyene antibiotic 1.2 Imidazole and triazole 1.3 Allylamines 1.4 Echinocandin 1.5 Others 2 Dandruff shampoos

List of antifungal drugs

Antifungals work by exploiting differences between mammalian and fungal cells to kill off the fungal organism without significantly harming the host. Unlike bacteria, both fungi and humans are eukaryotes. The basic structure of fungal cells and human cells is nearly identical. This means it is more difficult to find a target for an antifungal medication to attack that does not also exist in the infected organism. Consequently, there are often side-effects to these drugs. Some of these side-effects can be life-threatening.

There are several classes of antifungal drugs.

Polyene antibiotic

The polyene antibiotics bind with sterols in the fungal cell wall, principally ergosterol. This causes the cell's contents to leak out and the cell dies. Animal cells contain cholesterol instead of ergosterol and so they are much less susceptible.

• Nystatin
  Amphotericin B
  Natamycin
  Rimocidin
  Filipin
  Pimaricin

Imidazole and triazole

The imidazole and triazole groups of antifungal drugs inhibit the enzyme cytochrome P450 14α-demethylase. This enzyme converts lanosterol to ergosterol, and is required in fungal cell wall synthesis. These drugs also block steroid synthesis in humans.

Imidazoles:

• Miconazole
  Ketoconazole
  Clotrimazole
  Econazole
  Mebendazole
  Bifonazole
  Butoconazole
  Fenticonazole
  Isoconazole
  Oxiconazole
  Sertaconazole
  Sulconazole
  Thiabendazole
  Tioconazole

The triazoles are newer, and are less toxic and more effective:

• Fluconazole
  Itraconazole
  Ravuconazole
  Posaconazole
  Voriconazole

Allylamines

Allylamines inhibit the enzyme squalene epoxidase, another enzyme required for ergosterol synthesis:

• Terbinafine - marketed as Lamisil in North America and the UK
  Amorolfine
  Naftifine
  Butenafine

Echinocandin

Echinocandins inhibit the synthesis of glucan in the cell wall, probably via the enzyme 1,3-β glucan synthase:

• Anidulafungin
  Caspofungin
  Micafungin

Others

Others:

• Flucytosine is an antimetabolite.
  Griseofulvin binds to polymerized microtubules and inhibits fungal mitosis.
  Fluocinonide
  Gentian Violet
  Ciclopirox is a fungicidal
  Tolnaftate is a fungicidal

Alternatives:

• Tea tree oil -- ISO 4730 ("Oil of Melaleuca, Terpinen-4-ol type")

Dandruff shampoos

Antifungal drugs are often found in dandruff shampoos. Among the most common are pyrithione zinc and selenium sulfide.