Intro to Antifungals Flashcards
What are the targets of antifungal treatment?
1) DNA synthesis
2) Mitosis
3) Cell wall (beta-1,3-glucans)
4) Protein synthesis
what is ergosterol?
- Ergosterol is found mainly in fungal cell membranes.
- It has a role in regulation the membrane permeability.
what is beta-1,3-glucans?
they make up 50-60% of the dry weight of the Fungal CELL WALL.
Polyenes is an antifungal - how does it work?
Polyenes is associated with ergosterol. Causes the loss of membrane integrity and leakage of K+ , leading to cell death.
What type of antifungals are Amphotericin B and Nystatin are examples of?
Polyenes (antifungal)
Amphotericin B is effective on most fungi with medical importance.
What fungi does Amphotericin B particularily work on?
1) Aspergillus spp
2) Candida spp
3) Cryptococcus spp
What are the adverse effects of Amphotericin B?
Allergic reaction
Nephrotoxicity
How is amphotericin B adminstered?
Parenterally (anyway that is not oral)
What is Nystatin used for?
superficial infections e.g. oral/vaginal candidiasis
What is pulmonary aspergillosis?
fungal infection of lungs that usually affects those with an underlying condition e.g. TB, COPD.
How do Allylamines (antifungals) work?
Inhibit ergosterol synthesis
What type of antifungal is terbinafine?
Allylamine (works to inhibit ergosterol synthesis)
What are the adverse effects of allylamines?
Liver toxicity –> jaunice, hepatitis.
What are allylamines used for?
1) dermatophyte infections e.g. Athletes foot (topical use)
or Scalp ringworm (systemic oral use)
How do Azoles work?
Inhibit ergosterol synthesis
what is the spectrum of activity of azoles?
Broad spectrum (ie. both yeasts and filamentous fungi)
What type of antifungal (azole) is Clotrimazole - is it a Imidazole or Triazole?
Clotrimazole is an Imidazole
What type of antifungal (azole) are the following:
- fluconazole
- itraconazole
- voriconazole
Triazoles
what are the adverse effects of Azoles?
- Hepatotoxicity
- inhibits Cytochrome P450 enzymes
Rank the following triazoles in order of their spectrum :
fluconazole, isavuconazole, itraconazole?
1) Fluconazole (only works on yeast)
2) itraconazole (works on yeast and apergillus)
3) Isavuconazole (ALL)
what are imidazoles used for?
Superficial infections (topical) e.g. Candidiasis or Dermatophyte infection
What are triazoles used for?
Systemic infections (oral / parenteral admin) e.g.aspergillosis / candidiasis.
What do Echinocandins act on?
Inhibit beta-1,3-glucan synthase which results in abnormal cell wall construction.
What type of antifungal is Aniidulafungin ?
Echinocandin
What is the spectrum of activity of Echinocandins?
- Aspergillus and Candida spp.
- Misses certain mould and cryptococcus
How are echinocandins administered?
For systemic infections given parenterally
How do 5-fluorocytosines work?
Inhibits RNA/ protein and DNA synthesis
what is the spectrum of activity of 5-fluorocytosine?
works on yeasts only e.g.candida and cryptococcus spp.
What are the adverse effects of 5-fluorocytosine?
Bone marrow suppression
How does griseofulvin work?
Inhibition of fungal mitosis
what is griseofulvin used for?
Dermatophyte infection
What drugs require therapeutic drug monitoring?
- Itraconazole
- 5-fluorocytosine
- Voriconazole
