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Antifungal Drugs |
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- Polyenes -- Amphotericin B, nystatin
- Imidazoles - ketoconazole, fluconazole, itraconazole
- 5-fluorocytosine
- Griseofulvin
- In general, treatment is prolonged, cost is high, side-effects can be significant
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Polyenes - Amphotericin B |
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- Macrolide ring - series of double bonds
- Mechanisms - bind to ergosterol in the fungal cell membrane
- Administration - poorly soluble , prepare suspension, no electrolytes, slowly infuse iv
- Toxicity -- absorbs to renal tissues, causes necrosis, loss of renal function
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Imidazole Drugs |
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- Related family of drugs - all contain an imidazole, or triazole, ring structure
- Ketoconazole, fluconazole, clotrimazole
- Pharmacokinetics vary - in general easier to give, less toxic, sometimes less effective,
Inhibit ergosterol synthesis
- Use for combined therapy with amphotericin
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5-Fluorocytosine |
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- Converted to 5-fluoropyrimidine by fungal cells -- inhibits nucleic acid synthesis
- Chief use -- cryptococcal meningitis
- Crosses blood-brain barrier
- Resistance can develop
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Iodides |
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- KI -- given orally or by injection
- Seems effective for various types of chronic granulomatous infections
- Mechanism unknown -- not anti-fungal in vitro
- Causes iodide toxicity -- but is reversible
- Low cost
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Griseofulvin |
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- Dermatophyte infection
- Give with fatty meal -- increases absorption
- Concentrates in keratinized epithelium
- Inhibits fungal cell wall metabolism
- Usually non-toxic - can cause GI disturbances
- Contraindicated in pregnancy -- can be teratogenic
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