Antifungals Flashcards
True or False: Antifungals are a group of antibiotics
False: They are a group of antimicrobials
What potent antifungal is used to treat deep mycoses, administered primarily IV, and not given PO because it is poorly absorbed from the GI tract?
Amphotericin B
What is the mechanism of action for Amphotericin B
It binds to and damages ergosterol
What is ergosterol?
A major component of the fungal membrane
What does damaging ergosterol do?
It creates holes in the fungal cell membrane and allows for critical cellular components to leak from the fungal cell
When critical cellular components leak from the fungal cell wall, what effect does this produce?
A fungicidal or fungistatic effect based on the concentration of the drug at the fungal infection site
What is the most common and most significant side effect of Amphotericin B?
Nephrotoxicosis
Due to its nephrotoxic side effects, what form was created to better deliver Amphotericin B to the fungal infection?
Liposomal form
What is the Liposomal form of Amphotericin B?
Amphotericin B is encapsulated in a liquid capsule that reduces nephrotoxicity
Azoles are otherwise know as what?
Imidazole derivatives
What are the two groups of Azoles?
Imidazoles and Triazoles
Imidazoles contain what?
Two nitrogen atoms
Triazoles contain what?
Three nitrogen atoms
What are commonly used Azoles?
Ketoconazole Itraconazole Fluconazole Miconazole Voriconazole Clotrimazole
What is the prototype imidazole?
Ketoconazole
Which antifungal is the first drug of choice for long-term treatment?
Imidazoles
What is the mechanism of action for azoles/imidazoles?
Interfere with the enzyme that synthesizes erogosterol molecule
How many days of treatment does it take for imidazoles to become fungicidal?
5 to 10 days
Do imidazoles cause nephrotoxicity?
No
What are the most common side effects of imidazoles?
GI side effects
Vomiting at higher doses occurs more commonly in cats
In what imidazole/azole has hepatotoxicity been reported?
Ketoconazole
What is a more potent antifungal than ketoconazole, is more effective at treating Aspergillus than ketoconazole, causes fewer GI side effects?
Itraconazole
What is one of the drugs of choice for treating guttural pouch mycosis in horses caused by Aspergillus?
Itraconazole
What other antifungal is more potent than ketoconazole, is less effective at treating deep mycoses than itraconazole and does not require an acidic pH to be absorbed like the other antifungals?
Fluconazole
Which antifungal is the drug of choice for treating mycotic meningitis?
Fluconazole
Fluconazole is excreted mostly in the kidney, and thus achieves therapeutic concentrations in the urine making it the drug of choice to treat what?
Fungal cystitis
Which antifungals are used to treat topical yeast infections and superficial dermatophytes?
Clotrimazole & Miconazole
Which antifungal is used for intranasal infusions to treat nasal aspergillosis?
Clortimazole
