Antifungal

Question 1

What’s antifungal drugs

Answer 1

Chemical agents that selectively eliminates fungal pathogens

Question 2

Types of fungi

Answer 2

1. Based on feeding; Saprophytic and parasitic
2. Based on site of infection; Superficial infection: Dermatophytes and mucosa(yeasts)
   Systemic infection

Question 3

Examples of superficial infections

Answer 3

MOD

1. Mucosamycosis- candida infection of body mucosa e.g thrush, oidiomycosis, yeast infection
   Caused by Candida albicans
2. Onchomycosis -fungal infection of nails; White, proximal, distal
3. Dermatophytosis- fungal infection of skin and hair

Question 4

Examples of systemic fungal infection

Answer 4

Primary and opportunistic pathogens, spread from lungs primarily.
Examples include; Aspergillosis, cryptococcosis, pneumocystosis, histoplasmosis, coccidioidomycosis etc

Question 5

Risk factors for mycosis

Answer 5

1. Excessive use of antibiotics
2. Steroid treatments
3. HIV/aids infection
4. Cancer chemotherapy
5. Very old or very young people
6. Diabetes

Question 6

Risk factors for mycosis

Answer 6

1. Excessive use of antibiotics
2. Steroid treatments
3. HIV/AIDS infection
4. Cancer chemotherapy
5. Very old or very young people
6. Diabetes

Question 7

Classes of antifungals

Answer 7

4-APE

Azole, Allylamine, Anti metabolite, antimitotic

Polyene antifungal, echinocandins

Question 8

Polyene antifungals card

Answer 8

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

Question 9

Azole antifungal card

Answer 9

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

Question 10

Allyamine card

Answer 10

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

Question 11

Echinocandins card

Answer 11

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

Question 12

Anti metabolite card

Answer 12

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

Question 13

Anti-mitotic antifungal

Answer 13

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