Antifungal Flashcards
What’s antifungal drugs
Chemical agents that selectively eliminates fungal pathogens
Types of fungi
- Based on feeding; Saprophytic and parasitic
- Based on site of infection; Superficial infection: Dermatophytes and mucosa(yeasts)
Systemic infection
Examples of superficial infections
MOD
- Mucosamycosis- candida infection of body mucosa e.g thrush, oidiomycosis, yeast infection
Caused by Candida albicans - Onchomycosis -fungal infection of nails; White, proximal, distal
- Dermatophytosis- fungal infection of skin and hair
Examples of systemic fungal infection
Primary and opportunistic pathogens, spread from lungs primarily.
Examples include; Aspergillosis, cryptococcosis, pneumocystosis, histoplasmosis, coccidioidomycosis etc
Risk factors for mycosis
- Excessive use of antibiotics
- Steroid treatments
- HIV/aids infection
- Cancer chemotherapy
- Very old or very young people
- Diabetes
Risk factors for mycosis
- Excessive use of antibiotics
- Steroid treatments
- HIV/AIDS infection
- Cancer chemotherapy
- Very old or very young people
- Diabetes
Classes of antifungals
4-APE
Azole, Allylamine, Anti metabolite, antimitotic
Polyene antifungal, echinocandins
Polyene antifungals card
Macrocyclic molecules with multiple double bonds, product of Streptomyces species
E.g Amphotericin B, Nystatin, Natamycin, Filipin. (FANN)
Mechanism of action
Binding to ergosterol and causing membrane leakages
Uses
1. Amphotericin B: Systemic infections such as Aspergillosis, cryptococcosis, etc
2. Nystatin: oral, vaginal, git candidiasis
3. Natamycin: superficial eye infection
Adverse effects: phlebitis, chills, cardiac arrest, liver damage, hearing loss, bone marrow toxicity,rash and renal toxicity
Azole antifungal card
Pentacyclic aromatic compound with nitrogen atom and two double bonds. Divided into: Imidazole, triazole, thiazole
Imidazole: popular -zole apart from fluconazole
Triazole: fluconazole, etc
MOA: block ergosterol synthesis by inhibiting lanosterol-14-alpha-demethylase
Thiazole: abafungin(antifungal and sporocidal)
MOA: inhibit sterol 24c-methyl transferase
Uses: known
Adverse effects: Traizoles cause nausea, vomiting, liver toxicity.
Ketoconazole worse due to hepatotoxicity
Allyamine card
Simplest stable unsaturated amine.
E.g: -Fine. Terbinafine, butenafine, amorolfine
MOA: block ergosterol synthesis by inhibiting enzyme squalene epoxidase
Uses: effective against Dermatophytes
Adverse effects: visual disturbance, taste disturbance, git probs, headache, dizziness, liver toxicity
Echinocandins card
Newest of antifungals
(-fungin) e.g Micafungin, caspofungin, Anidulafungin
MOA: block synthesis of beta (1,3) glucan by inhibiting enzyme beta glucan synthase
Use: NOT USED ORALLY due to low bioavailability. Administered to immunocompromised patients
Adverse effects: local phlebitis, fever, haemolysis, liver probs
Anti metabolite card
E.g Flucytosine
MOA: inhibits RNA and DNA synthesis through inhibition of thymidylate synthetase
Use: + amphotericin b for cryptococcal meningitis
Adverse effects: hepatic dysfunction, jaundice, headache, hallucinations, anaphylaxis, blood dyscrasia,renal failure
Anti-mitotic antifungal
E.g Griseofulvin
MOA: inhibits mitosis in fungi by binding to microtubules
Uses: treat fungal skin infection. ( reduce oral contraceptives due to CY-P450 enzyme)
Adverse effects: headaches, dizziness, vomiting, diarrhea,insomnia, rash