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26 Cards in this Set
- Front
- Back
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What was the early sulfonamide discovered by Domagk in 1932?
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Prontosil rubrum (metabolized by the liver to Sulfonamide)
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What are sulfonamides structurally similar to?
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PABA
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What is the mechanism of action of sulfonamides?
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Inhibits Dihydropteroate Synthase in the folic acid synthesis pathway
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Why are humans not affected by sulfonamides?
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We can't synthesize our own folic acid, we get it from our diets
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How have bacteria become resistant to sufonamides?
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Increased production of PABA
Dihydropteroate synthase altered so that it doesn’t recognize sulfonamides Reduce sulfonamides uptake |
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What are the kinetics of sulfonamides?
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Good urine solubility, high levels in urine
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What are the clinical uses of sulfonamides?
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Acute urinary tract infections
Patients allergic to penicillins Otitis media |
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What are the adverse reactions associated with sulfonamides?
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Allergies, Stevens-Johnson syndrome (autoimmune blistering)
Kernicterus (drug displaces bilirubin, which damages brain) Hemolytic anemia (in G6PD def) |
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What's the relation of sulfonamides to G6PD deficiency?
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Can cause hemolytic anemia because it coverts GSH to GSSG, creating excess NADP when the body converts it back
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In what parts of the world do you find increased incidence of G6PD deficiency?
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Where malaria is a big deal (Africa, parts of central and south America, and Asia)
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What's the mechanism of action of Trimethoprim?
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Bacteriostatic - Inhibits Dihydrofolate reductase in the folic acid synthesis pathway
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How is Trimethoprim selective for bacteria?
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Drug binds preferentially to the bacterial form of DHF reductase 1000x better than the mammalian form (unlike methotrexate)
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What's the benefit of combining Sulfonamides and Trimethoprim?
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You get good synergistic inhibition of the folic acid pathway without added toxicity = bacteriocidal.
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What's the effect on DNA synthesis when you block the folic acid pathway?
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BlInhibiting folic acid reduction blocks synthesis of dTMP from dUMP = impairs DNA synthesis due to a lack of thymidine.
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What is Sulfamethoxazole?
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a sulfonamide. Often combo'd 5:1 with trimethoprim.
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What are the clinical uses of Trimethoprim/Sulfamethoxazole?
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Chronic urinary tract infections
Pneumocystis pneumonia Traveler’s diarrhea |
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What are the adverse reactions associated with Trimethoprim/Sulfamethoxazole?
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Sulfonamide toxicities
GI distress (n/v due to loss of nl flora) Folate deficiency (long term use) |
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Name 4 Quinolones.
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CIPROFLOXACIN
Nalidixic Acid Levofloxacin Gatifloxacin |
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What does DNA gyrase do?
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Plasmid packaging enzyme
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Mechanism of action of quinolones?
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blocks DNA replication and transcription by inhibiting DNA gyrase (topoisomerase II) and topoisomerase IV
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What's the mechanism of action of Ciprofoxacin?
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Quinolone: inhibits DNA gyrase
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What the spectrum of Ciprofoxacin?
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Broad
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What are the clinical uses of Ciprofoxacin?
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Urinary tract infections gonorrhea
C. trachomatis, M. avium, B. anthracis Skin, bone and joint infections |
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What are the adverse reactions of Ciprofoxacin?
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GI, nausea, rashes, dizziness, headache, delirium
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What is special about the quinolone Levofloxacin?
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It's flouranated and has better activity against gram positives (strep)
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Which 2 quinolones are more potent against gram +?
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Levofloxacin
Gatifloxacin |
