Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
26 Cards in this Set
- Front
- Back
|
Mechanism of action of sulfonamides
|
competes with PABA during folate synthesis to inhibit dihydropteroate synthase
|
|
|
Why don't sulfonamides have an effect on human folate?
|
sulfonamides only inhibit folate SYNTHESIS. humans don't synthesize folate. sulfonamides have no effect on folate use
|
|
|
Dihydropteroate synthase is inhibited by high levels of...
|
sulfonamides
|
|
|
Trimethoprim inhibits which enzyme?
|
DHFR, dihydrofolate reductase. now dihydrofolate cannot become FH4 (tetrahydrofolate) to be used in purine synthesis
|
|
|
3 ways of resistance to sulfonamides
|
very high PABA levels, folate production enzyme with low sulfonamide affinity, low sulfonamides permeability, mutant target enzymes
|
|
|
Major mode of distribution of sulfonamides
|
oral
|
|
|
Sulfonamide-trimethoprim together have what sort of effect?
|
synergistic. both work on sequential steps of folate synthesis/usage
|
|
|
Sulfacetamide, a topical sulfonamide, has a side effect of metabolic acidosis. Why?
|
it is a carbonic anhydrase inhibitor = no CO2 removal in the lung = acidosis
|
|
|
Stevens-Johnson syndrome is a fatal side effect of which class?
|
sulfonamides
|
|
|
Major sulfonamide adverse reactions
|
crystalluria, rashes (even the fatal Steven-Johnson syndrome), hemolytic/aplastic anemia
|
|
|
Why doesn't trimethoprim (inhibitor of folate usage) lead to human cell death?
|
human DHFR is way less reactive to trimethoprim (50,000x less active against humans)
|
|
|
Sulfonamides alone are (bactericidal or bacteriostatic)?
|
bacteriostatic
|
|
|
Sulfonamides + trimethoprim are (bactericidal or bacteriostatic)?
|
bactericidal
|
|
|
Trimethoprim is usually given by what route?
|
alone orally; with sulfa drugs it is IV
|
|
|
Trimethoprim concentrates in what parts of the body?
|
prostate and vagina
|
|
|
Megaloblastic anemia is seen in patients on which drug?
|
trimethoprim (mimics folate deficiency)
|
|
|
Quinolones mechanism of action
|
block DNA gyrase (topoisomerase 2) + topoisomerase 4. both
|
|
|
DNA gyrase function
|
relaxation of DNA coils. helps unwind DNA
|
|
|
Topoisomerase 4 function
|
relax DNA coils
|
|
|
Function of Qnr proteins against quinolones
|
protects DNA gyrase from the quinolones
|
|
|
Anthrax is treated with...
|
ciprofloxacin
|
|
|
Trimethoprim + Sulfamethoxazole is first line therapy for ...
|
P. jiroveci pneumonia
|
|
|
Pyrimethamine + sulfadiazine is first line therapy for what infection?
|
toxoplasmosis
|
|
|
Pyrimethamine + sulfadiazine is second line therapy for what infection?
|
malaria
|
|
|
Arthritis-like symptoms are a common side effect of which drug?
|
Fluoroquinolones
|
|
|
Chlamydial urethritis and cervicitis is best treated with which drugs?
|
levofloxacin and ciprofloxacin;
|
