Antifungals, antimycobacterials, antivirals Flashcards
(122 cards)
What’s a genus of bacteria that includes many species of pathogens?
mycobacterium
What are the targets of antimycobacterials?
enzymes that mycobacteria use to build their cell walls
How are mycobacteria different than typical bacteria?
easier to control but harder to treat because they replicate slower.
CAN exist in a dormant state which makes them resistant to nearly all abx
What’s the standard treatment in active mycobacterial disease?
- Rifampin
- Isoniazid
- Pyrazinamide
- Ethambutol
Note: takes weeks to get susceptibility results
How does isoniazid work?
- bactericidal
- inhibits mycolic acid synthesis!
- effective against active AND dormant TB
- acts as a weak MAO-I (careful with SSRI/SNRI)
- alters pyridoxine metabolism (give B6 to all patients)
What are the two most important drugs for TB?
- isoniazid
- rifampin
What is isoniazid active against?
M. tuberculosis and M. kansasii
How is isoniazid clinically utilized?
mycobacterial infections
When is isoniazid your DOC?
latent TB, active TB
What are ADRs of isoniazid?
hepatotoxicity, peripheral neuropathy (use pyridoxine), hemolysis in G6PD deficiency
What are examples of rifamycins?
- rifampin
- rifabutin
- rifapentine
- rifaximin
What’s the MOA of rifamycins?
- bactericidal
- Inhibits DNA-dependent RNA polymerase
- very good oral bioavailability
- resistance emerges when drug is used alone
What should you always screen for drug ineractions?
rifamycins – extremely potent CYP450 inducers!!
also, reduced effectiveness of oral contraceptives
What are rifamycins GOOD for?
mycobacteria
What are rifampins moderate for?
staph, acinetobacter, enterobacterciae
What are rifamycins utilized for?
mycobacterial infections – usually in combo w/ deep seeded “typical” bacterial infections (MRSA) or if prosthetic material
When is rifamycin your DOC?
TB = tuberculosis, MAC = mycobacterium avium complex
What are ADRs of rifamycins?
orange-red colored secretions (urine, tears)
Do rifamycins have DIs?
many due to enzyme induction
What’s the MOA of pyrazinamide?
- bacteriostaticuncertain but requires bioactivation via hydrolytic enzymes to form pyrazoic acid
- shortens duration 9m - 6m
NOT pyridoxine
AVOID IN PREGNANCY
When are pyrazinamides clinically active?
M. tuberculosis
When are pyrazinamide clinically utilized and is your DOC?
active TB
What are the ADRs of pyrazinamide?
polyarthralgia (40%), hyperuricemia, mylagia, maculopapular rash, porphyria, photosensitivity
What’s the MOA of ethambutol?
- bacteriostatic
- inhibits formation of arabinoglycan, component of mycobacterial cell wall
- only 1st 2 months of tuberculosis therapy
- **NOT recommended in children <5yo **