The Mess That Is Micro - VIII - Antifungals

Question 0

Side effect of ketoconazole?

Answer 0

Testosterone synthesis inhibition –> gynecomastia, liver disfunction.

Remember: con men ketch girls with big boobs (ketoconazole)

Question 1

Azoles

Answer 1

Inhibition of fungal sterol (ergosterol) synthesis by inhibiting cytochrome p450 enzyme which converts lanosterol to ergosterol.

Remember: a zoo has everything from lions (lanosterol) to goats (ergosterol).

Question 2

Clinical use for itraconazole

Answer 2

Remember: it rains on the plains.

Blastomyces, coccidioides, histoplasma

Question 3

Fluconazole use?

Answer 3

Chronic suppression of cryptococcal meningitis in AIDs patients

Question 5

Flucytosine

Answer 5

Inhibits DNA and RNA biosynthesis by conversion to 5-FU by cytosine deaminase. Replaces uracil with 5-fluorouracin in fungal mRNA. Use for systemic fungal infections (meningitis caused by Cryptococcus) in combination with amphoteracin B.

Remember: Flu lost her sight and became less animated at the age of 5.

Question 5

Terbinafine

Answer 5

Inhibits the fungal enzyme squalene epoxidase
Dermatophytoses - especially onychomycosis - fungal infection of finger or toe nails.
GI upset, headaches, hepatotoxicity, taste disturbance.

Remember: turbins on your fingers, turbins on finger of squalling babies.

Question 6

Echinocandins

Answer 6

Capsofungin, micafungin, anidulafungin.

Inhibits cell wall synthesis by inhibiting synthesis of beta (1,3)-D-glucan
Use for invasive aspergillosis, candida (the main component of their cell walls is beta (1,3)-D-glucan.
Gi upset, flushing through histamine release.

Remember: fun gin makes the construction workers build badly, vomit, aspirate (aspergillus) candy (candida) and flush / turn red.

Question 8

Griseofulvin

Answer 8

Binds polymerized microtubules. Interferes with microtubule function, disrupts mitosis, deposits in keratin containing tissues such as nails.
Use as oral treatment of superficial infections, inhibits growth of dermatophytes (tinea, ringworm).
Toxicity: teratogenic, carcinogenic, confusion, headaches, increased p450 and warfarin metabolism.

Remember: greasy tubes full of carrots (keratin)

Question 9

Amphoteracin b

Answer 9

A polyene, along with nystatin.

Binds ergosterol, unique to fungi, forms membrane pores that allow leakage of electrolytes.
Use for serious systemic mycoses, crypticoccus, blastomyces, coccioides, histo, candida, mucor, intrathecally for fungal meningitis. Supplement k+ and mg2+.
Toxicity: fevers and chills, hypotension, nephrotoxicity, arrhtyhmias, anemia, iv phoebitis. Hydration decreases nephrotoxicity. Liposomal amphoteracin decreases toxicity.

Remember: AMPHOteraciN
Anemia / arrhythmia
Magnesium loss
Potassium loss, phlebitis
Hypotension

Nephrotoxic

Question 10

Nystatin

Answer 10

A polyene. Binds ergosterol and forms membrane pores like amphoteracin.
Use topically bc it is too toxic for systemic use.
Clinical use: swish and swallow for oral candidiasis, topical for diaper rash or vaginal candidiasis.

Remember: polly the nymph - polyenes include nystatin and amphoteracin