Antifungal drug
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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.
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[edit] 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.
[edit] Polyene antimycotic
A polyene is a circular molecule consisting of a hydrophobic and hydrophilic region. This makes polyene an amphoteric molecule. The polyene antimycotics bind with sterols in the fungal cell membrane, principally ergosterol. This changes the transition temperature (Tm) of the cell membrane from a fluid to a more crystalline state. As a result, the cell's contents leak out (usually the hydrophilic contents) and the cell dies. Animal cells contain cholesterol instead of ergosterol and so they are much less susceptible. (Note: by reducing the hydrophobic chain on the polyene creates a more active sterol binding agent. Therefore, reducing the hydrophobic region too much results in binding to cholesterol, making it toxic to animals.)
- Natamycin -- 46 Carbons, binds well to ergosterol
- Rimocidin
- Filipin -- 35 Carbons, binds to cholesterol (toxic)
- Nystatin
- Amphotericin B
[edit] 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 - marketed as Lotrimin or Lotrimin AF
- Econazole
- Bifonazole
- Butoconazole
- Fenticonazole
- Isoconazole
- Oxiconazole
- Sertaconazole
- Sulconazole
- Tioconazole
The triazoles are newer, and are less toxic and more effective:
- Fluconazole
- Itraconazole
- Ravuconazole
- Posaconazole
- Voriconazole
- terconazole
[edit] 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 - marketed as Lotrimin Ultra
[edit] Echinocandin
Echinocandins inhibit the synthesis of glucan in the cell wall, probably via the enzyme 1,3-β glucan synthase:
- Anidulafungin
- Caspofungin
- Micafungin
[edit] Others
Others:
- Ciclopirox is a fungicidal
- Flucytosine is an antimetabolite.
- Griseofulvin binds to polymerized microtubules and inhibits fungal mitosis.
- Gentian Violet
- Haloprogin
- Tolnaftate is a fungicidal
- Undecylenic acid is a fungistatic
Alternatives:
- Tea tree oil -- ISO 4730 ("Oil of Melaleuca, Terpinen-4-ol type")
- Neem Seed Oil
- Coconut Oil
- Zinc dietary supplements or natural food sources, including pumpkin seeds and chick peas
- Selenium dietary supplements or natural food sources, particularly brazil nuts
[edit] Dandruff shampoos
Antifungal drugs are often found in dandruff shampoos. Among the most common are pyrithione zinc and selenium sulfide.
[edit] See also
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| Antibiotics | Griseofulvin, Hitachimycin, Natamycin, Nystatin |
| Topical Azoles | Clotrimazole, Econazole, Fluconazole, Ketoconazole, Miconazole, Oxiconazole, Sertaconazole, Sulconazole, Tioconazole |
| Other topicals | Ciclopirox, Ethylparaben, Flucytosine, Salicylic acid, Selenium sulfide, Terbinafine, Tolnaftate |
| For systemic use | Amphotericin B, Anidulafungin, Caspofungin, Griseofulvin, Itraconazole, Terbinafine, Voriconazole |
| Other | Posaconazole, Thiabendazole, Tea tree oil |
