Flashcards in 9.1 Sulfa Deck (24):
Broadly speaking, what is the mechanism of sulfa drugs?
Prevent folate synthesis- which is necessary for nuclei acid production
What are the 2 mechanisms sulfa drugs use?
Sulfamethoxazole mimic PABA --> competitively inhibits DHT synthetase
Trimethoprim (TMP) – analog of dihydrofolate --> DHF reductase
What is the IV sulfa drug?
Trimethroprim – sulfamethoxazole
What are the PO sulfa drugs?
Trimethroprim – sulfamethoxazole (TMP-SMZ)/Bactrim/Septra
What G+ coverage do Sulfa drugs have?
What G+ are NOT covered by Sulfa? Why?
Enterococcus- Can bring in folate from host
What G- coverage do sulfa drugs have?
What is Dapsone used for?
Leprosy/ mycobacterium leprae
What are the common side effects of Sulfa?
Rash (including Stevens-Johnson syndrome)
What are special risks with Dapsone?
Methemoglobinemia = decreased ability of RBC to carry O2
What was the first Quinilone?
What G+ coverage does Nalidixic acid have?
What G- coverage does Nalidixic acid have?
What is the mechanism of Nalidixic acid against G+/G-?
G-: DNA gyrase
= both interfere with unwinding of DNA
What are the IV quinolones?
What are the PO quinolones?
How do bacteria become immune to quinilones?
Mutation of topoisomerase IV/gyrase
Overexpression of reflux pumps
What is the spectrum for Quinilones?
G+ = strep, staph
G- = H. Flu, Enterobacteriacea, Neisseria
Anaerobic = Clostridia, Bacteroids
Atypical = Chlamydia, Mycoplasma, Legionella
Mycobacteria = TB, MAC, Mycobacterium leprae
What does Cipro cover?
R1 = piperazine – enhance G- activity (similar to PCN)
Weak G+ activity – Not to treat Strep Pneumo infection
What does Levofloxacine cover?
2x more potent than ofloxacin
Less active against G- than Cipro
More active against G+ than Cipro
Ok for strep pneumo including PCN resistant
What is the difference between cipro/levo?
Cipro- more G-, weaker G+, pseudomonas
Levo- More G+, weaker G-
What do Moxifloxin and Gemifloxacin cover?
Enhance activity against strep pneumo including PCN resistant
Less active against G- (i.e. pseudomonas)
Good coverage for anaerobes
What populations are quinilones contraindicated with?