Anti-Fungals Flashcards
Griseofulvin
- MOA: Fungistatic; Binds microtubules > inhibiting mitosis, NA/protein synthesis, breaks down IC organelle membranes
- Uses: dermatophytes
- AE: cats more susceptible, vomiting/diarrhea, teratogenic, myelosuppression, phototoxicity
- Contraindications: pregnancy, hepatic dz, immunosuppressed cats (FIV, FeLV)
What MUST you check for prior to prescribing Griseofulvin for a cat?
FIV/FeLV - myelosuppressive
Amphotericin B
- MOA: Fungistatic or fungicidal; binds ergosterol - incr permeability and leakage - death
- Uses: Histoplasma, Blastomyces, Cryptococcus, Coccidiodes, Candida, Rhodotorula, Mucor; Aspergillus IS RESISTANT
- AE: nephrotoxicity (vasoconstriction), hypokalemia, chills, anorexia, nausea, vomiting, seizures, hypotension, fever, cardiac arrest, anaphylactoid rxns, phlebitis
- Contraindications: renal dz
Ketoconazole
- MOA: Fungistatic; Fungicidal (high) - blocks conversion of lanosterol to ergosterol (P450 inhibition in fungi/mammals)
- Uses: broad (yeasts to systemic mycoses) - NOT feline sporothricosis
- AE: cats > dogs, nausea, vomiting, diarrhea, anorexia, hepatophaty, abortigenous, alopecia, pruritis, coat lightening
- Contraindications: pregnancy, if on cyclosporine (uses cytochrome P450)
Itraconazole
-
MOA: Fungistatic/fungicidal based on concentration; blocks conversion of lanosterol to ergosterol (mainly fungly only P450 effects)
- Safer than Keto
- Uses: broad (yeasts to systemic mycoses)
- Used for pulse treatment
- AE: Well tolerated, nausea, anorexia, vomiting, idiosyncratic hepatotoxicity (reversible), potential vasculitis at high doses
- Contraindications: none
Compare and contrast itraconazole and ketoconazole
Itraconazole has better absorption, longer duration of action, it’s less toxic, and more potent (5-100 times)
Flucoconazole
-
MOA: blocks conversion of lanosterol to ergosterol; cytochrome P450 (mainly fungal)
- SAFEST AMONG AZOLES
- Uses: broad (yeasts to systemic mycoses), better CNS and ocular distribution than Itra, low protein binding > Blastomycosis, cryptococcosis
- AE: vomiting, nausea, less toxic than Keto
- Contraindications: none
Terbinafine
- MOA: Fungicidal; inhibits squalene epoxidase, (> fungal)
- Uses: superficial mycoses (yeasts and dermatophytes), better than griseofulvin and ketoconazole for dermatophytes
- AE: fungicidal concentration in tissues/blood for 4-8wks after discontinuation
- Contraindications: none
Iodides
MOA: unknown; suspect incr proteolysis and neutrophilic fxn
Uses: Sporotrichosis (horses esp.)
AE: Iodism- nausea, vomiting, diarrhea (best w/ food), twitching, hypothermia, scaling, alopecia
Contraindications: none
*mostly used in large animals
Which antifungals target membrane function?
Amphotericin B
What antifungals target ergosterol synthesis?
Fluconazole, Itraconazole, Terbinafine
What is pulse therapy?
the administration of large (suprapharmacologic) doses of drugs in an intermittent manner to enhance the therapeutic effect and reduce the side effects; itraconazole
