AbxinterferingwithFolatesynthesisC Flashcards
Disruption of the folate pathway is generally what in single agent therapy?
Bacteriostatic
What are the 2 enzyme targets for bactericidal folate antagonists ?
Dihydropteroate sythetase, Dihydrofolate reductase
Folate is a cofactor for what?
Transfer of 1-carbon groups ad electrons in intracellular synthesis and degradation reduction
Sulfonamides target bacteria that are used in what pathway?
PABA pathway
T/F- Sulfonamides are bacteriostatic against gram +/- bacteria?
TRUE
What are the 3 major groups of sulfonamides?
Oral absorbable, Oral nonabsorbable, Topical agents
What are the oral absorbable sulfonamides?
Sulfadiazine- uti, uncomplicated malaria. Sulfadoxine, Sulfisoxazole- otitis media, UTI, chloroquine resistant malaria, drug resistant malaria, and toxoplasma gendii
Sulfamethoxazole- URI, UTI, prophylaxis and tx of p carinii (HIV)
What is the nonabsorbable agent and its uses?
Sulfasalazine, Delayed release in RA, UC, enteritis
What is sulfasalazine not indicated for?
Infectious disease inflammations
What are the topical agents are their uses?
Sodium sulfacetamide,Ophthalmic, Chlamydia trachorra,/ silver sulfadiazine ñ burn infection prophylaxis
What is the most common cause of preventable blindness worldwide? How is it treated?
Chlamydia trachoma,Sodium sulfacetamide
What special populations need to be considered for sulfa use?
Pregnant women and neonates
What is trimethoprim?
Competitive inhibitor of dihydrofolic acid reductase, Similar to sulfonamides but more potent and has increased penetration to the prostate
What are indications for trimethoprim?
Community acquired UTI or prophylaxis of UTI, RARELY used ALONE
What 2 agents create bactrim?
Sulfamethoxazole+ trimethoprim
What are the clinical uses of bactrim?
Pneumocystis carinii, bacterial diarrhea, prophylaxis- UTI, PCP, peritonitis
What category of drugs inhibit DNA topoisomeroses?
Quinolones
What category of drugs inhibit DNA dependant RNA polymerase?
Directly: rifampin, Indirectly: nitrofurantoin
Are quinolones cidal or static?
Bactericidal
Which quinolone has gram ñ coverage w/ moderate gram + activity?
Ciprofloxacin
Which quinolone has excellent gram ñ coverage w/ improved gram +
Levofloxain, moxifloxacin
Which quinolone has continued gram +/- coverage with increased anaerobic coverage?
Trovafloxacin
Which atypical pneumonia organisms and intracellular pathogens are also covered by quinolones?
Atypical: Chlamydia pneumo, mycoplasma pneumo, Intracellular: legionella, mycobacteria tb, mycobacteria avium complex
In general, how often are quinolones used and what are their clinical uses?
VERY frequently, UTI, sinusitis, mycobacterial infections, bacterial diarrhea, soft tissue/bone/joint infections, gonococcal and chlamydial, pneumonia, post-exposure prophylaxis for anthrax
Which quinolone is FDA restricted to life or limb threatening infections?
Trovafloxacin
Why should fluoroquinolone not be used for routine URIs or skin/soft tissue infections?
We want to prevent resistance! Save these for last to minimize resistance
Quinolones are widely distributed throughout the body, including what typically underpenetrated area?
Prostate
What are the most common ADRs of quinolones? Rare?
N/V/D, Seizure w/use of NSAIDs, blood dyscrasias, irreversible peripheral neuropathy
Which quinolone is approved to treat mild- moderate CAP d/t multi-drug resistant strep pneumo?
Gemifloxacin
What is metronidazole (flagyl) spectrum of activity?
Anaerobic and protozoan infections. -amebiasis, trichomonias, cns infections, c. diff, and h. pylori
Can metronidazole be given in pregnancy?
NOT 1st TRIMESTER, category B in 2/3
With what drug interaction can metronidazole cause disulfiram-like rxns? What is this rxn?
ETOH! Flushing, HA, N/V, sweating, tachycardia
When is nitrofurantoin cidal? Static?
High concentrations= cidal Low concentrations= static
What is nitrofurantoinís biggest indication and why?
UTI – d/t increased concentrations in the urine
What pt population should you avoid nitrofurantoin in?
Elderly
What are indications of polymyxin B? what is its spectrum of activity?
Gram negative Topical prep, antibiotic ointments, washes for wounds, surgery prep
Why is polymyxin B limited to topical use?
High nephro/neurotoxicity
Can you give polymyxin B IV or IM?
Only in life or death situations
