9.1 Sulfa II Flashcards
What is the mechanism of Metronidazole/flagyl?
Small molecule diffuses into cells, once activated releases free radicals that break DNA.
What class of bacteria does Metronidazole target? Examples?
Anaerobes- they have the e- txp chain needed to activate free radicals
C. Diff, B. fragilis
Do bacteria become resistant to Metronidazole?
Rare-
What are the SA of metronidazole?
Nausea, Epigastric dyscomfort Metallic taste Furring of tongue Headache, dizziness, neuropathy – high dose and long duration Disulfiram – like reaction
What is the MOA of bacitracin?
Inhibits cell wall synthesis
What does bacitracin cover?
G+ cocci and bacilli
Neisseria; H. flu
Treponema pallidum; Actinomyces; Fusobacterium
What doesn’t bacitracin cover?
Enterobacteriaceae; Pseudomonas; Candida; Norcardia
How is bacitracin prepared?
PO Only
IV- D/C’d due to nephrotoxicity
What is mupirocin?
Topical 2% med
What does mupirocin cover?
G+ (i.e. Strep pyogenes & MSSA & MRSA)
G- (i.e. H. Flu; Neisseria; B. Catarrhalis; Pasteurella Multocida)
What is the mechanism of mupirosin?
Reversibly inhibits Aminoacyl-tRNA synthetase Prevents AA attaching to tRNA (i.e. prevent “loading” or “charging”) stop protein synthesis
What is the indication for mupirosin?
Nasal MRSA
What is the most important characteristics of mycobacterium?
4 layers of cell wall, outer made from mycelia acid
Many efflux pumps
Can hide INSIDE patient’s own cells
What are the most common anti-mycobacterial agents?
Isoniazid- most common
Rifamycins- (RNA polymerase)
Some aminoglycosides (streptomycin)
Some macrolides (azithromycin)
What is the mechanism of Isoniazid (INH)?
Inhibits mycolic acid synthesis- which makes up the cell wall
Prodrug- diffuses into mycoplasma where activated by KatG that then interferes with mycolic acid
What is the indication for INH/Isoniazid?
TB
How do cells become resistant to INH?
Mutation of activating enzyme
What are the SE of INH?
Rash, fever, dry mouth
Methemoglobinemia
Hepatoxicity (esp. together with 2E1 inducers)
2E1 converts INH to hepatotoxic metabolite
Neuropathy – to prevent give with vit B6
Arthritic symptoms
What are special considerations with INH?
Monitor LFTs
Many DDI- induces 2E1 (same as ETOH, many other meds)
What is the indication for Pyrazinamide?
Given with INH for TB
What is the mechanism of Pyrazinamide
Not fully known Targets enzymes for synthesis of mycolic acid Reduction of intracellular pH Disrupt membrane transport ** Only works at acidic pH
What are the SA of pyrazinamide?
Arthralgias, anorexia, N/V
Fever, malaise, dysuria
Hepatotoxicity
Increase uric acid higher risk for gout
What is Ethambutol?
MOA
TB drug
Target the synthesis of mycobacterial cell wall
Disrupt the assembly of cell wall
What are the SA of ethambutol?
Optic Neuritis –> decrease visual acuity and red-green color blindness
Rash, pruritus
Joint pain, GI upset, HA, dizziness
What is the tx for multi-drug resistant TB?
Bedaquiline
What is the mechanism of Bedaquiline?
Inhibits bacterial ATP synthase
What are the notable SA of bed aquiline?
QT prolongation
Hepatitis
