Microbiology- Antifungals

Question 1

Prophylaxis for CD4

Answer 1

TMP-SMX for pneumocystis pneumonia

Question 2

Prophylaxis for CD4

Answer 2

TMP-SMX for pneymocystis and toxoplasmosis

Question 3

Prophylaxis for CD4

Answer 3

Azythromycin or clarithromycin for M. avium complex

Question 4

Amphotericin B

Answer 4

MOA: Binds ergosterol in fungal cell membrane and punches hole. AmphoTERacin tears wholes in fungal cell membrane

CU: Serious, systemic mycosis. Cryptococcus, Blastomycies, Coccidioides, Histo, Candida, Mucor. Intrathecally for fungal meningitis. Supplement K+ and Mg+ d/t altered renal tubule permeability.

Tox: Fever/chills, hypotension, nephrotox, arrhythmias, anemia IV phlebitis. Hydration and liposomal preparation decrease nephrotox. and tox in general. “Amphoterrible”

Question 5

Nystatin

Answer 5

MOA: Same as Amphotericin B. Binds ergosterol.

CU: “Swish and swallow” oral candidiasis, topical for diaper rash or vaginal candidiasis.

Tox: Too toxic for systemic use, topical preps only.

Question 6

Flucytosine

Answer 6

MOA: Inhibits DNA and RNA biosynthesis by conversion to 5-fluorouracil by cytosine deaminase.

CU: Systemic fungal infections (esp. cryptococcal meningitis) in combination with Amp B.

Tox: BM suppresion

Question 7

Clotrimazole, fluconazole, itraconazole, ketoconazole, miconazole, voriconazole

Answer 7

Azoles
MOA: Inhibit sterol synthesis by inhibiting P-450 that converts lanosterol to ergosterol

CU: Local and less serious systemic mycoses. Fluconazole for chronic suppression of cryptococcal meningitis in AIDS pats and candidal infections of all types. Itraconazole for Blasto, cocci, histo. Clotrimazole and miconazole for topical fungal infections.

Tox: Testosterone synthesis inhibition (gynecomastia), liver dysfunction.

Question 8

Terbinafine

Answer 8

MOA: Inhibits the fungal enzyme squalene epoxidase.

CU: Dermatophytoses, (onychomycosis)

Tox: GI Upset, headaches, hepatotox, taste disturbances

Question 9

Anidulafungin, Caspofungin, Micafungin

Answer 9

Echinocandins
MOA: Inhibit cell wall synthesis by inhibiting synthesis of beta-glucan

CU: Invasive aspergillosis, candida

Tox: GI upset, flushing d/t histamine release.

Question 10

Griseofulvin

Answer 10

MOA: Interferes with microtubule formation, disrupts mitosis, deposits in keratin-containing tissues