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9 Cards in this Set
- Front
- Back
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Folate antagonists
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Sulfonamides
Trimethoprim and Pyrimethamine Methotrexate (anti- cancer drug) Dapsone (anti leprosy drug) |
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Folate
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Folate is required for DNA synthesis in both bacteria and animals
Humans cannot synthesise Folate, it must be provided in the diet Bacteria synthesise their own folate from precursors like p-aminobenzoic acid (PABA) Antibiotics (sulfonamides) may compete with PABA for active site on enzyme (dihydropteroate synthase) |
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Sulfonamides
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Sulfisoxazole
Sulfadiazine Sulfamethaxazole Sulfadoxine -dont worry about time Being a structural analogue of PABA, sulfonamides competitively inhibit the dihydropteroate syhthase and the synthesis of folic acid in microbes |
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Sulfonamides used for
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uncomplicated mild urinary tract infections
Pneumocystis carinii |
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Cotrimoxazole
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A fixed dose combination of sulfamethaxazole and trimethoprim is called as Cotrimoxazole
Causes sequential block of folate metabolism Sulfamethaxazole and trimethoprim individually they are bacteriostatic. Together they are Bactericidal & Synergistic |
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Trimethoprim Methotrexate, Pyrimethamine MOA
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block dihydrofolate reducatase (humans have this aswell)
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Toxoplasmosis and P. Carinii
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Sulfadiazine + pyrimethamine
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Adverse effects of sulfonamides
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-disulfide like reaction
Hypersensitive reaction; Stevens-Johnson syndrome (look at pic) -Crystalluria (precipitation of drug-alkaline drug, acidic urine, drug clumps)…(Can be treated by NaHCO3) = white urine -ptn should be told to drink lots of water Hemolysis in those with G-6-PD deficiency |
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-female w/ UTI goes to party and starts throwing up, why?
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-disulfide reaction, on sulfonamides, which drug?
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