Griseofulvin
Cyclopirox
Azoles:
• | (used mostly for topical therapy) |
• | miconazole (Micatin, Monistat) |
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• | (broadest in vitro spectrum of activity) |
• | (bind more weakly to mammalian cyt P450, therefore fewer side effects and interactions) |
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Allylamines
Polyenes
Class: | Mechanism of Action: |
(griseofulvin) | interferes with microtubule assembly |
azoles | inhibits cytochrome P450 system this is the reason for azole related drug interactions (preferentially fungal); therefore leading to enzyme dysfunction in the conversion of lanosterol to ergosterol |
allylamines | interferes with enzyme squalene epoxidase (= necessary for the first step in the conversion of squalene to ergosterol) |
polyenes | bind to ergosterol and punch holes in the fungal cell membrane |
Summary:
• | all (except griseofulvin) target ergosterol the essential sterol in fungi cell membranes, while cholesterol is the essential sterol in humans |
• | only terbinafine and (amphotericin B at high doses) are fungicidal |
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