Unit 4 Fungi and Antifungal Medication

Question 1

candida

Answer 1

• beefy red erythema
• can cause inflammation
• likes moist environments

Question 2

histoplasma

Answer 2

-thermally dimorphic

Question 3

Amphotericin (Ampho-terrible)

Answer 3

• MOA: inhibits ergosterol, but also cholesterol
• Pharmacokinetics: IV OR TOPICAL ONLY, renal and hepato-biliary
• Spectrum: BROAD SPECTRUM, drug choice for SYSTEMIC INFECTIONS
• Adverse Rxn: NEPHROTOXICITY (80%), anemia

Question 4

Nystatin

Answer 4

• MOA: inhibits ergosterol, but also cholesterol
• Pharmacokinetics: TOPICAL ONLY (not orally absorbed)
• Spectrum: SUPERFICIAL CANDIDAL INFECTION
• Adverse Rxn: well tolerated when given topically, some GI upset when given for oral candidiasis

Question 5

Caspofingin (enchinocandin)

Answer 5

• MOA: inhibits synthesis of cell wall
• Pharmacokinetics: IV INFUSION ONLY, levels dec. by P450 inducers
• Spectrum: ASPERGILLIS (if refractory to ampho B)
• Adverse Rxn: infusion related sx

Question 6

MOA of Triazoles

Answer 6

-MOA: inhibit fungal P450, which inhibits ergosterol, selective

Question 7

Fluconazole

Answer 7

• Pharmacokinetics: IV or oral, renal excretion, enters CNA
• Spectrum: MOUTH, THROAT, VAG candidiasis, can enter CNS
• Adverse Rxn: well tolerated, some GI upset, can’t be used in pregnancy (cat D)

Question 8

Itraconazole

Answer 8

• Pharmacokinetics: IV, oral, hepatic metabolism
• Spectrum: dermatophytosis, onychomycosis
• Adverse Rxn: n/v, diarrhea, headache, INHIBITS CYP450

Question 9

Terconazole

Answer 9

• Pharmacokinetics: TOPICAL only (t and t clue)
• Spectrum: vaginal candidiasis
• Adverse Rxn: none

Question 10

ketoconazole (imidazole)

Answer 10

• MOA: inhibit P450 ergosterol synthesis inhibiting membrane permeability
• Pharmacokinetics: IV, oral, topical, hepatic metabolism
• Spectrum: systemic infections, DERMATOLOGIC INDICATIONS
• Adverse Rxn: HEPATOTOXICITY, INHIBITS CYP450 and testosteron synthesis

Question 11

Clotrimazole (Imidizole)

Answer 11

• MOA: inhibit P450 ergosterol synthesis inhibiting membrane permeability
• Pharmacokinetics: TOPICAL ONLY
• Spectrum: ORAL AND VAG CANDIDIASIS
• Adverse Rxn: none

Question 12

Triazoles

Answer 12

• fluconazole,
• itraconazole
• terconazole

Question 13

Terbinafine

Answer 13

-MOA: inhibits squalene oxidase reducing ergosterol synthesis
-Pharmacokinetics: oral and topical, metabolized by hepatic P450
Spectrum: ONYCHOMYCOSIS of FINGER/TOE NAILS, athlete’s foot
-Adverse: INHIBITION of CYP450

Question 14

Flucytosine

Answer 14

• MOA: converted 5FU in fungi- inhibits thymidylate synthesis and DNA synthesis
• Pharmacokinetics: well absorbed, renally eliminated
• Spectrum- serious infections of cryptococcosis and candidiasis
• Adverse: BONE MARROW DEPRESSION, skin rashes

Question 15

Griseofulvin

Answer 15

• MOA: binds to fungal microtubules, inhibiting mitosis
• Pharmacokinetics: poor oral absorption, improved with fatty meal
• Spectrum: severe dermatophytosis of skin, hair, finger/toe nails
• Adverse: HYPERSENSITIVITY RXNS, GI distress, headache, confusion