L27: Sulfa Flashcards
Sulfa are competitive inhibitors of _____
dihydropteroate synthase
How do Sulfa drug inhibit folate synthesis?
mimick PABA (end result: no DNA synthesis)
Sulf drugs have more bacteriostatic effect, but the exception is ____
TMP-SMX
Which organisms are sensitive to sulfa drugs?
Those that make their own folic acid
- Those that obtain pre-formed folate are resistance (human cells)
Trimethoprim and Pyrimethamine inhibit conversion of DHF acid to ____. They inhibit the enzyme ___
THF acid; DHFR
Mutated ____ lowers drug affinity in sulfa drugs
dihydropteroate synthase
Most sulfa drugs have good oral availability, except ___
sulfasalazine
Which sulfa is poorly absorbed, but active in bowel lumen?
A. sulfasalazine
B. sulfadiazine
C. sulfamethoxazole
A. sulfasalazine
Which two sulf are topical agents?
A. sulfasalazine
B. sulfadiazine
C. sulfamethoxazole
D. silver sulfadiazine
E. sulfacetamide mafenide
D. silver sulfadiazine
E. sulfacetamide mafenide
which two sulf drugs are absorbed/excrete rapidly?
Sulfamethoxazole/sulfadiazine
_____ has topical anti-inflammatory effects for UC and in RA
Sulfasalazine
____ mainstay for 2nd and 3rd degree burn therapy, which is effective against bacteria and fungi
Silver Sulfadiazine
Sulfacetamide is available as topical (Klaron) or opthalamic (Bleph). What are the uses for topical? opthalamic?
topical
- acne
- bacterial infections
opthalamic
- pink eye
- trachoma
_____ is also used in burn therapy. but, since its metabolite inhibits CA, it may lead to met acidosis.
Mafenide
Sulfamethoxazole must be given with ___ while sulfadizine must be given with ____
Sulfamethoxazole + TMP
Sulfadiazine + Pyrimethamine
TMP-SMX is preg cat __ while sulfadiazine is used to prevent ___ transmission
D; T. gondii
True or False: Trimethoprim+Sulfamethoxazole (TMP-SMX) are bactericidal and give dual inhibition
True
Use of TMP-SMX?
- Community acquired MRSA/ORSA
True or False: Rickettsiae is stimulated by TMP-SMX
True
True or False: Oral sulfonamides/trimethoprim can be used to treat UTI’s and prostatitis
True
True or False: Trimethoprim + Sulfmethoxazole can treat complicated and uncomplicated UTI’s
True
True or False: Oral sulfonamides and TMP can be used for respiratory infections, but not usually for pneumonia
True
TMP-SMX can treat PCP (pneumocystitis pneumonia) caused by _____
pneumocystis jirovecii
AE with sulfa drugs?
- hypersensitivity
- skin rash
- photsensitivity
- crystalluria
- SJS
- kernicterus
- bilirubin can cross BBB
Sulfoamides inhibit ___ while trimethoprim and pyrimethamine inhibit ____
dihydropteroate synthase; dihydrofolate reductase
True or False: TMP-SMX combo is commonly used for UTI’s, respiratory infections, and some GI
True
True or False: Bactrim (TMP-SMX) is pregnancy cat D, should be avoided when possible
True
