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25 Cards in this Set
- Front
- Back
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sulfonamides are structurally similar to
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p-aminobenzoic acid (PABA)
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what solutions are sulfonamides more soluble in
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alkaline
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sulfonamide MOA
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inhibit dihydropteroate synthesis and folate production in bacteria which require PABA (can't use exogenous folate)
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what bacteria do sulfonamides actually stimulate
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rickettsiae
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what bacteria are sulfonamides ineffective against
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anaerobes
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what is sulfonamides synergistic with
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inhibitors of dihydrofolate reductase (trimethylprim or pyrimethamine)
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sulfonamide resistance
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1) overproduction of PABA 2) enzyme with low affinity for sulfonamides 3) impair permeability of sulfonamides
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metabolism of sulfonamides
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portion acylated or glucuronidated in liver; excreted in urine via glomerular filtration
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what limits usefullness of mafenide acetate (a sulfonamide topical agent)
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absorbed from burn sites and metabolite inhibits carbonic anhydrase and can cause metabolic acidosis
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Steven Johnson syndrome
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<1% treatment courses of sulfonamides; fatal type skin and mucous membrane eruption
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urinary tract disturbances with sulfonamide use
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may precipitate in urine (neutral and acidic pH); treated via Na-bicarb administration and hydration
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hematopoietic disturbances of sulfonamides
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hemolytic or aplastic anemia, granulocytopenia, thrombocytopenia, or leukemoid rxns
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trimethoprim MOA
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selectively inibits bacterial dihydrofolic acid reductase = no purine synthesis
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pyrimethamine
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another benzylpyrimidine that selectively inhibits dihydrofolic acid reductase of protozoa compared to mammal cells
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trimethoprim in vaginal and prostatic fluids
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concentrates in these locations, thus has more antibacterial activity that many other antimicrobial drugs
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trimethoprim-sulfamethoxazole treatment is useful in
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P jiroveci pneumonia, shigellosis, systemic salmonella infections, UTIs, prostatitis, and some nontuberculous mycobacterial infections; others…the list goes on
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pyrimethamine with sulfonamide
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treatment of leishmaniasis and toxoplasmosis; falciparum malaria
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prdictable adverse side effects of trimethoprim
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megaloblastic anemia, leukopenia, and granulocytopenia
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Fluoroquninolones (-oxacins) MOA
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block bacterial DNA synthesis by inhibiting topoisomerase II (gyrase) and IV
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topoisomerase II inhibition
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relaxation of supercoiled DNA required for normal transcription and replication
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topoisomerase IV inhibition
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interferes with separation of replicated chromosomal DNA into daughter cells during division
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activity of fluoroquinolones
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gram-neg aerobic bacteria; new agents have gram-pos coverage
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how quickly can resistance appear in fluoroquniolones used alone
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once in 10^7 to 9, especially in staph, pseudomonas, and serratia
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why aren't fluoroquinolones recommended to patients under 18
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may damage growing cartilage and cause an arthopathy (although reversible)
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risk factors for tendinitis with fluoroquinolone use
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advanced age, renal unsufficiency, and concurrent steroid use
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