Pharmacology - Antifungals

Question 1

Amphotericin B:

• M of A?
• Absorption?
• Excretion?
• Spectrum?
• Adverse reactions?

Answer 1

• Binds to ergosterol; punches hole in membrane
• IV or topical only
• Slow renal plus hepato-biliary
• Deep, nasty, serious; Opportunistic (serious) - candida - aspergillus
• nephrotoxicity with anemia (no EPO); shake and bake (fever, shakes)

Question 2

Nystatin:

• M of A?
• Absorption?
• Excretion?
• Spectrum?
• Adverse reactions?

Answer 2

• Binds to ergosterol; punches hole in membrane
• Topical
• Candida albicans (super. oropharangeal/vaginal thrush)
• mild GI if used as swish and spit

Question 3

Caspofungin:

• M of A?
• Absorption?
• Excretion?
• Spectrum?
• Adverse reactions?

Answer 3

• Inhibits synthesis of of cell wall ergosterol; inhibit B glucan
• IV
• Decrease CYP450
• Opportunistic (serious) - candida - aspergillus
• Rash

Question 4

Fluconazole:

• M of A?
• Absorption?
• Excretion?
• Spectrum?
• Adverse reactions?

Answer 4

• Like imidazoles but more selective fungal P450 inhibition
• IV/PO enters CNS;
• Renal
• Candida albicans (super. oropharangeal/vaginal thrush)
• Well tolerated, lesser effect on CYP450

Question 5

Itraconazole:

• M of A?
• Absorption?
• Excretion?
• Spectrum?
• Adverse reactions?

Answer 5

• Like imidazoles but more selective fungal P450 inhibition
• IV/PO
• Hepatic
• Tinea unguium (super. onochomychoses (toe nail/ fingernail infection)), Deep, nasty, serious
• Inhibits CYP450; diarrhea

Question 6

Ketoconazole:

• M of A?
• Absorption?
• Excretion?
• Spectrum?
• Adverse reactions?

Answer 6

• Inhibit P450 ergosterol synthesis; inhibit 14a demethylase
• IV/po/topical on full stomach
• Hepatic
• Opportunistic (serious) - candida - aspergillus
• Inhibits CYP450; hepatotoxicity; decrease cortisol and testosterone

Question 7

Clotrimazole/Miconazole:

• M of A?
• Absorption?
• Excretion?
• Spectrum?
• Adverse reactions?

Answer 7

• Inhibit P450 ergosterol synthesis; inhibit 14a demethylase
• Topical
• Tinea etc. (superficial, athletes foot, ringworm, jock itch); Candida albicans (super. oropharangeal/vaginal thrush)
• Inhibits CYP450; hepatotoxicity; decrease cortisol and testosterone?

Question 8

Terbinafine:

• M of A?
• Absorption?
• Excretion?
• Spectrum?
• Adverse reactions?

Answer 8

• Inhibit ergosterol synthesis; inhibit squalene oxidase
• po/topical
• Hepatic CYP450
• Tinea unguium (super. onochomychoses (toe nail/ fingernail infection))
• Inhibits CYP450. headache, diarrhea, rash

Question 9

Flucytosine:

• M of A?
• Absorption?
• Excretion?
• Spectrum?
• Adverse reactions?

Answer 9

• Converted to 5FU in fungi; inhibits DNA synthesis
• PO
• Renal
• Deep, nasty, serious; Opportunistic (serious) - candida - aspergillus
• Skin rash, bone marrow depression

Question 10

Griseofulvin:

• M of A?
• Absorption?
• Spectrum?
• Adverse reactions?

Answer 10

• Binds fungal microtubules inhibiting mitosis
• poor po, need fatty meal
• Tinea unguium (super. onochomychoses (toe nail/ fingernail infection))
• Hypersensitivity reactions, confusion