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19 Cards in this Set
- Front
- Back
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What is the mechanism of action of the fluoroquinolones?
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They are inhibitors of the bacterial DNA gyrase in gram negatives and the topoisomerase in gram positives
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How does resistance to fluoroquinolones occur?
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They binding sites on the gyrase and topoisomerase enzymes are mutated, lowering the affinity for drug binding
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What are the major fluoroquinolones?
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1) ciprofloxacin
2) levofloxacin 3) gatifloxacin 4) moxifloxacin |
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What are the adverse effects of fluoroquinolones?
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1) GI disturbances
2) rash 3) tendon ruptures |
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Describe the spectrum of fluoroquinonlones
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They have a broad spectrum and are widely used
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Describe the absorption of fluoroquinolones, what can inhibit their absorption?
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They have nearly 100% PO absorption but it is inhibited by metal ions
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What is the mechanism of action of rifampin and for what is it primarily used?
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It inhibits DNA-dependent RNA polymerase and is used in the treatment of TB and carriers of meningococcus
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What is the difference in spectrum among the fluoroquinolones?
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Levofloxacin, gatifloxacin, and moxifloxacin have higher activity against strep pneumoniae and MDRSP than the older ciprofloxacin
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Why is selective toxicity of folic acid possible when treating infection?
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Humans and bacteria have different sources of folic acid
bacteria make their own folic acid and humans get it in the diet |
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What is the mechanism of action of sulfonamides?
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They act as structural analogs of p-aminobenzoic acid and competitively inhibit dihydropteroate synthetase, the enzyme responsible for the first step in the synthesis of folate
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How does resistance to sulfonamides occur?
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Increased synthesis of p-aminobenzoic acid and synthesis of an altered dihydropteroate synthetase that does not bind sulfonamides
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What are the major therapeutic uses of sulfonamides?
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Uncomplicated UTI and toxoplasmosis in combination with pyrimethamine
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What are the members of the sulfonamides class?
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1) sulfisoxazole - UTIs
2) sulfamethoxazole - UTIs 3) sulfacetamide - ophthalmic infection 4) silver sulfadiazine - burns 5) sulfasalazine -ulcerative colitis |
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What are the most common adverse effects associated with the use of sulfonamides?
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1) kernicterus in newborns due to displacecent of bilirubin
2) hypersensitivity 3) crystalluria |
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What is the mechanism of action of trimethoprim?
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It interferes with the folate utilization by inhibiting dihydrofolate reductase, the enzyme that reduces dihydrofolate to tetrahydrofolate
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Why are trimethoprim and sulfamethoxazole used together?
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They act on the same pathway and are synergistic in blocking the formation of folic acid
They are bactericidal |
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What is the drug of choice for the treatment of pneumocystis jiovecii?
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TMP-SMZ
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What is an alternative to TMP-SMZ used in the treatment of pneumocystis and is approved for prophylaxis?
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Pentamidine
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What are the adverse effects of trimethoprim?
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It can interfere with folate metabolism in malnourished individuals and lead to megaloblastic anemia, leukopenia, and granulocytopenia
It can also cause Steven's Johnson syndrome |
