Anti-Fungals Flashcards
Most powerful
Amphotericin B
Most used
the -azoles
Ketoconazole, itraconzaole, fluconazole
Which drug is produced by penicillium?
Griseofulvin
Griseofulvin
produced by penicillium
insoluble (in water)
fungistatic
only effective against dermatophytosis
Griseofulvin Mechanism of action
anti-mitotic (esp inhibits DNA synthesis)
incorporated into keratin and reaches skin in 4-8 hrs.
gone in 2-3 days
Griseofulvin metabolism
variably absorbed (better with food) oxidized in liver (way faster metabolism than humans)
______ weeks of tx required for successful therapy of dermatophytosis
4
(many patients req. 3+ months)
What decreases absorption of Griseofulvin
phenobarbitol
Why don’t we use Griseofulvin anymore?
GI (Naseau, v, d)
bone marrow suppression (esp cats, esp with FIV/FeLV or persians etc)
Teratogenicity (brain, skeletal malformations)
not absorbed orally
Amphotericin B
dehydration increases toxicity
amphotericin B
well tolerated, especially the ___________ preparation of Amphotericin B, which has less side effects & longer 1/2 life.
liposomal
adverse effects of amphotericin
thrombophlebitis, nephrotoxicity, hypokalemia, resistance overtime
Which anti-fungal do you choose last? When there’s no other options
amphotericin B
All the -azoles we have to know are
oral
ketoconazole
lipophilic, broad specturm, liver metabolism, interacts with P450-affinity for fungal and mammalian, GI and liver toxicity adverse effects common
itraconazole
inc. affinity for fungal enzyme, fewer adverse effects, broad spectrum, poor penetration in CSF, less liver toxicity, vasculitis in high doses
fluconazole
SAFEST-highest specificity for fungal enzymes(thus least drug interactions), broad spectrum, well tolerated in cats
-azoles all interact with
cytochrome P450
safest Antifungal - little/no side effects with mammals
terbinafine
terbinafine
dermatophytosis, malessezia, well tolerated, inhibits ergosterol synthesis lipophilic& keratinophilic (persists in nails)
