Antifungal Agents

Question 0

Flucytosine therapeutic uses

Answer 0

Used to treat systemic candidiasis, cryptococcus neoformans, aspergillus

Administered with amphotericin B

Question 1

Flucytosine

Answer 1

Nucleic acid synthesis inhibitor
Inhibits the enzyme thymidylate synthase - can’t make thymidine

Converted to 5-FU by cytosine deaminase, 5-FU is converted to 5-FdUMP which inhibits thymidylate synthase

Question 2

Griseofulvin

Answer 2

Mitosis inhibitor - disrupts assembly of. Mitotic spindles
Accumulates in keratin precursor cells
Allows new growth of hair, skin, nails free of fungal infection
*takes a long time

Dermatophytic infections of hair, skin, nails (not candidiasis)-ringworm in children

Question 3

Terbinafine

Answer 3

Squalene Epoxidase inhibitor - fungicidal
Can’t covert squalene to lanosterol -> ergosterol
-accumulation of squalene

Used topically for ringworm (tinea corporis, cruis, pedis, capitus) caused by dermatophytes

Question 4

Itraconazole

Answer 4

14alpha-sterol demethylase inhibitor (a fungal CYP P450)

-destabilization of cell membrane

Question 5

Amphotericin B

Answer 5

Binds to ergosterol and Inhibits fungal membrane stability

Broad spectrum for nearly all life-threatening systemic mycoses including cryptococcal meningitis
-used to rapidly tx then replaced by an stolen

Question 6

Flucocytosine adverse rxns

Answer 6

Hematologic - bone marrow suppression (5-FU)
Hepatotoxicity
Can inhibit CYP 3A4 - contraindicated in pts taking certain drugs ( can cause arrythimias)

Question 7

Griseofulvin adverse rxns

Answer 7

Headaches

Acute intermittent porphyria

Question 8

Terbinafine adverse rxns

Answer 8

Skin rxns (cutaneous lupus erythematosis, Steven Johnson syndrome) 
Hepatotoxic

Question 9

Itraconazole adverse rxns

Answer 9

HTN, Hypokalemia, edema, cardiac suppression

Numerous drug interactions due to inhibition of CYPs -toxicity

Question 10

Nystatin

Answer 10

Binds to ergosterol and Inhibits fungal membrane stability

Cutaneous, vaginal, mucosal, and esophageal candidiasis
Swish and swallow for oral thrush

Question 11

Amphotericin B adverse rxns

Answer 11

Infusion related effects - cytokine storm (fever, chills, HTN)
- minimized with pretx with acetaminophen or corticosteroids

Renal toxicity
Hematologic toxicity

Question 12

Caspofungin

Answer 12

Fungicidal
Inhibits cell wall synthesis

IV therapy of deeply invasive aspergillosis in pts unresponsive or intolerant to traditional agents (amphotericin and itroconazole), and systemic candidiasis