UTIs Flashcards
Methenamine
MOA: decomposes to formaldehyde and ammonia in acidic urine, formaldehyde binds amino groups and inhibits proteins, bactericidal
Coverage: gram neg, esp E coli, tx for chronic UTIs
AE: no systemic efffects, may see crystalluria
CI: hepatic and renal insufficiency
Nitrofurantoin
MOA: interfere w/enzymes, activity higher in acidic urine
Coverage: Gram pos and neg, NOT effective against proteus/pseudomonas. Used to tx acute and chronic UTIs
Kinetics: rapid/complete oral absorption, highly protein bound-no effect in serum, excreted in urine where it is active.
AE: Colors urine brown, causes pulmonary fibrosis in the old or w/chronic use.
CI: avoid if creatinine clearance <50, pregnancy, impaired renal function, allergy
Norfloxacin
UTIs and prostatis
Ciprofloxacin
MOA: inhibition of DNA gyrase (topoisomerase II), bactericidal,
Coverage: Gram pos AND neg, covers pseudomonas and MRSA, anthrax prophylaxis
Kinetics: oral admin, liver metabolism, renal excretion, antacids w/Mg, Fe, Ca interfere w/absorption, penetrates bone/joints
AE: GI upset, QT prolongation, Tendon rupture
Shortcomings: Not effective vs. S pneumoniae/anaerobes, does not penetrate CNS
CI: pregnant/nursing, kids <18
Levofloxacin
Community acquired pneumonia
Ofloxacin
Prostatits, STDs (not syphillis), some systemic infections, TB
Moxifloxacin
MOA: inhibits topoisomerase II (DNA gyrase) and IV
Coverage: Broad spectrum, effective against penicillin resistant S. pneumoniae, LESS effect vs. pseudomonas and enterobacteriacea, improved anaerobe coverage, tx of exacerbations of chronic bronchitis, acute sinusitis, pneumonia
Kinetics: 1/day oral admin, penetrates CNS and pulmonary tissues, metabolizd through glucuronide and sulfate conjugation (liver)
AE: ab pain, liver dysfunction, C. difficile overgrowth-pseudomembranous colitis
CI: moderate/sever hepatic insufficiency, QT prolongation, hypokalemia, pts on Class IA or III antiarrhytmics
Drug interactions: NSAIDs, antacids, TCAs, vit A derevatives, phenothiazines (none with digoxin, warfarin).
Gatifloxacin
Topical only, ocular infections
Gemifloxacin
Active against penicillin-resistant S pneumonia, Tx of CAP
Metronidazole
MOA: active form disrupts DNA helical structure–> inhibits nucleic acid syn –> death
Coverage: anaerobes below the diaphragm, Tx of RTIs, bone/joint infections, septicemia, endocarditis, pseudomembranous colitis
Kinetics: Oral/IV/topical admin, liver metabolism, urinary elimination
AE: disulfiram effect, candida overgrowth
Fidaxomicin
MOA: inhibits bacterial protein syn by binding to RNA pol
Coverage: narrow-spectrum, only Gram pos aerobes and anaerobes, no effect vs. gram neg, Tx of C. diff colitis in kids and adults
Kinetics: high fecal excretion
Mupirocin
MOA: RNA and protein inhibition, reversible binding to isoleucyl-tRNA synthetase
Coverage: S. aureus, GBS, MRSA (intranasal), bacteriostatic and low doses, bactericidal at high doses
Kinetics: topically to skin or nares
Tx of impetigo due to S. aureus or GBS
Polymixin B & E
MOA: binds to gram neg membrane phospholipids –> inc permeability –> loss of nutrients. Also binds and inactivates endotoxins.
Coverage: bactericidal against Gram neg bacilli esp pseudomonas and coliform (not effective vs proteus and neisseria).
Tx: Topical admin to wounds/burns, pseudomonas, UTI, septicemia/bacteremia, when other ABX are ineffective or CI
Kinetics: No oral admin, distribution after paraenteral is poor, kidney excretion is slow
AE: nephrotoxicity
Interactions: aminoglycosides, caphalothin, non-depolarizing muscle relaxants
