2/9/17 SMITH Antimicrobial IV TEST #2 Flashcards
What are antimetabolites involved in?
-Folate synthesis
What is PABA?
-Key intermediate in the synthesis of dihydrofolic acid
What enzyme do sulfonamides inhibit?
-Dihydropteroate synthetase
What enzyme do Trimethoprim inhibit?
-Dihydrofolate reductase
What are two key Antimetabolite drugs?
- Sulfamethoxazole (SMX)
- Trimethoprim (TMP)
What drug is structurally similar enough to PABA to compete for and inhibit dihydropteroate synthetase?
-Sulfamethoxazole (SMX)
What drug inhibits dihydrofolate reductase, which converts dihydrofolic acid to tetrahydrofolic acid?
-Trimethoprim (TMP)
T/F Humans lack the enzymes needed to convert PABA to tetrahydrofolic acid
True
T/F Bacterial growth is selectively inhibited via folate deficiency
True
T/F The higher the dose of the sulfamethoxazole the quicker it can outcompete and bind to enzyme
True
What sulfonamide antibiotic is short acting and only given topically?
-Silver sulfadiaxine
How is sulfamethoxazole given?
-Orally
Sulfamethoxazole bacteriostatic or bacteriocidal?
-Bacteriostatic
T/F sulfamethoxazole is usually prescribed alone
False
-It is usually prescribed with something else
What does sulfadiazine inhibit?
-Dihydropteroate synthetase
Sulfadizaine is given how and for what?
-Oral monotherapy for UTIs and burns
What is silver sulfadiazine given?
-Topically
What drug do you use to prevent and treat infections related to skin burns or superficial wounds?
-Silver sulfadiazine
What are two adverse effects of sulfadiazine and silver sulfadizaine?
- Sulfa-hypersensitivity
- photosensitivity
What is a major adverse effect of Trimethoprim?
-Pseudomembranous colitis (C diff overgrowth)
Trimethoprim Bacteriostatic or bacteriocidal?
-Bacteriostatic
What drug treats marrow poorly (bone marrow suppression)?
-Trimethoprim
What drug do you get if you combine TMP and SMX?
-Cotrimoxazole (Bactrim, Septra)
T/F The combination of TMP and SMX is more effective than either individual components
True
What is the drug of choice for treatment of Pneumocystis jiroveci (carini) pneumonia?
-Cotrimoxazole
T/F Cotrimoxazole is a time-dependent bactericidal drug
True
T/F the combination of TMP and SMX provides 2 step blockade of folate synthesis
True
What are two other medical uses for Cotrimoxazole besides treatment for pneumocystis?
- Gram + aerobes (recurrent UTIs)
- H. Influenzae (Respiratory and otitis)
What was the first sulfonamide drug?
-Prontosil
What does a prodrug require?
-Bioactivation (the body converts the drug to its active state)
What was the most consequential mass poisoning in the United states in the 20th century?
-Elixir sulfanilamide tragedy
What was added in the elixir sulfanilamide that made it sweet?
-Diethylene glycol
