Antifungals Flashcards
What are the three main groups of antifungals
Polyenes, azoles and echinocandins
Give two examples of polyene antifungals
Amphotericin B, Nystatin
What fungal infections do polyenes treat
S.nodosis and S.noursei
What is the mechanism of action of amphotericin B
It is used for systemic fungal infections. Amphotericin B binds to sterols in the cytoplasmic membrane of fungi and affects membrane permeability. There is leaking of intracellular cations ann this is followed by water.
What is an adverse affect associated with amphotericin
It is neprhotoxic
Gives two examples of azoles
Clotrimazole and fluconazole
What are azoles used to treat
Thrush (candida)
How are azoles such as clotrimazole and fluconazole given
They can either be given by systemic or topical application.
What is the mechanism of action of azoles
Azoles act by inhibiting demethylase enzyme which is required for ergosterol synthesis (a component of cell membranes in fungi). There is an accumulation of toxic sterols in the cell membrane.
Give three examples of echinocandins
Caspofungin, anidulafungin and micafungin
Which two types of fungi are treated using echinocandins
Candida and aspergillus.
Which fungi cannot be treated with echinocandins
Cryptococci
What is the mechanism of action of echinocandins
Echinocandins target beta glucan synthases and inhibit cell wall construction.
By what method are echinocandins given
By IV
What are dermatophytes
These are fungi that require keratin for growth
Which antifungals are used for treatment of deratophytes
Griseofulvin, terbinafine, flucytosine
What is terbinafine used to treat
Fungal nail infections.
What is the mechanism of action of terbinafine
Terbinafine inhibits ergosterol synthesis by inhibiting equalene epoxidase.
What is an adverse effect of terbinafine
GI upset.
What is griseofulvin used for
Fungal skin and nail infections
What is flucytosine used to treat
Systemic severe yeast infections
What is flucytosine usually used alongside
The polyene amphotericin B
What is the mechanism of action of flucytosine
It interferes with DNA synthesis.
What are the adverse effects associated with flucytosine
GI tract, hepatic and bone marrow toxicity.
