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27 Cards in this Set
- Front
- Back
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List drugs/drug classes that are used to treat UTIs
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Sulfonamides
Trimethoprim Fluoroquinolones Fosfomycin Nitrofurantoin |
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Whats the difference between a complicated and uncomplicated UTI?
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Uncomplicated UTIs have no predisposing conditions that would account for the bacteria in the bladder.
Complicated UTIs have a cause, like a stone, obstruction, spinal cord problem, drugs, opiods, CATHETERS, antibiotic resistance |
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Source of UTI bacteria typically?
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Anus or GI tract
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Types of UTI bacteria typically?
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Facultative gram - rods (eg E. coli 75-85%, Enterobacteriaceae)
Some gram + cocci |
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What are these classified as?
Sulfisoxazole Sulfamethoxazole Sulfazadine Sulfasalazine Sulfacetamide Silver sulfadiazine |
Sulfonamides
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MoA of sulfonamides?
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Inhibits bacterial synthesis of folic acid
Sulfonamides mimic PABA, the substrate for dihydropteroate synthetase |
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What are the resistance MoA(s) to sulfonamides?
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Self altered dihydropteroate synthetase dec's binding affinity
Efflux pumps Dec'd membrane permeability? Inc'd production of PABA to competitively inhibit sulfonamide Alternative pathway to synthesize (or obtain) folic acid |
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What is the clinical use of Sulfasalazine? MoA?
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Used to tx ulcerative colitis and other inflammatory bowel conditions
Its not well absorbed, so stays in gut, inhibiting arachadonic acid synthesis |
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What is the typical sulfonamide combo given?
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Sulfamethoxazole + Trimethoprim
In 5:1 ratio |
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Whats the MoA of Trimethoprim?
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Inhibits bacterial synthesis of folic acid, at a later step than Sulfamethoxazole but in the same pathway
Trimethoprim inhibits dihydrofolate reductase Sulfamethoxazole inhibits dihydropteroate synthetase |
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Why is folic acid even important for bacteria?
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Folic acid is converted to tetrahydrofolate which is used as a carbon donor to help convert uracil into thymidine, which is used in DNA synthesis (gcaT)
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Whats the spectrum of activity for Sulfamethoxazole/Trimethoprim (aka "bactrim")?
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Broad spectrum against gram - , gram + , atypicals
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What is Sulfamethoxazole/Trimethoprim used clinically for?
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UTIs
Respiratory infections Traveller's diarrhea (wiki) Acne Vulgaris (wiki) Some protozoa (wiki) |
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AEs for sulfonamides?
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Crystalluria (older sulfonamides can form crystals in urine due to their lower solubility)
Acute hemolytic anemia Rash (which can progress to Stevens-Johnson Syndrome) "my car is so fun, it has no AEs" |
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What is Stevens-Johnson Syndrome?
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Skin can sloth off, very dangerous
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DIs for sulfonamides?
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Anticoagulants(warfarin)
Sulfonylureas(can cause hypoglycemia) Hydantoin anticonvusants(phenytoin) |
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What are the first gen quinolones?
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Nalidixic acid (no longer avail)
Note first gen's weren't fluoronated yet |
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What are the second gen fluoroquinolones?
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Ciprofloxacin
Ofloxacin Norfloxacin (no longer avail) |
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What are the third gen fluoroquinolones?
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Gemifloxacin
Levofloxacin Moxifloxacin |
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MoA of fluoroquinolones?
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Inhibits DNA Gyrase and Topoisomerase 4
Result: DNA Gyrase makes its usual cut to relieve strain in unwound helix, but no ligase occurs, damaging bacterial DNA |
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What is the spectrum for fluoroquinolones?
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Broad spectrum(g-, g+), including:
Enterobacteriaceae MSSA ATYPICALS ANTHRAX(drug of choice) Mycobacterium tuberculosis(2nd line) |
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Which fluoroquinolones are clinically used for respiratory infections?
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Third gen fluoroquinolones
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Which fluoroquinolones are clinically used for UTIs?
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Any generation
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Which fluoroquinolones are clinically used for bacterial diarrhea(travellers diarrhea),eg against Shigella, Salmonella?
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Ciprofloxacin
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Caution(s) or Contraindication(s) for fluoroquinolones?
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Caution: Renally excreted(must adjust dose when impaired)
Contra: DO NOT USE FLUOROQUINOLONES DURING PREGNANCY |
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A patient has a urinary catheter, a complicated UTI, gram - and + bugs in his body. What drug combo should he take?
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Levofloxacin + Linezolid
Note: dont use Sulfamethoxazole + Trimethoprim in this case because he most likely has too much resistance built up |
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AEs for fluoroquinolones?
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-GI effects(N&V, abdominal discomfort)
-Photosensitivity -Ruptured Achilles tendon (rare) -Prolonged QTc interval, with the following risk factors: cardiac disease antiarrythmic drugs aging hypokalemia, hypomagnesemia macrolides that prolong QT |
