UTI and Fluoroquinolones

Question 1

Most common cause of UTI

Answer 1

e coli

Question 2

Urinary tract antiseptic

Answer 2

Methenamine - gets converted to formaldehyde

use with sulfa increases crystalluria

Question 3

Nitrofurantoin

Answer 3

• MOA – activated by bacterial nitroreductase yielding intermediates that damage DNA
• Human cells not as effective at activating nitro
• Bacteriostatic in low concentrations; bactericidal in high concentrations
• Activity enhanced by acidic urine (like methenamine)
• Use
o Prevention of UTI recurrence – can be used long-term
o Tx of uncomplicated lower UTIs (cystitis)
o Not for pyelonephritis

Renal elimination

Only active in low pH urine

SE - pneumonia, hepatotox, neuropathies, not for prego at term

Question 4

Fosfomycin

Answer 4

Good for cystitis

• MOA – blocks cell wall synth – enopyruvyl transferase needed to synthesize peptidoglycans
• Single dose orally adequate for cystitis

Gram -

Not for pseudomonas

Question 5

Phenazopyridine

Answer 5

Sulfa like

Analgesic for symptoms of UTI pain – basically IBU for bladder

Question 6

Quinolones

Answer 6

MOA - inhibit DNA gyrase (target for e coli) and TOPO IV (target for staph and strep)

Resistance - mutations, proteins that protect gyrase

Very broad spec: gram - and gram +

Use - UTI: cipro is best (pseudomonas)
cypro and levo are 1’ for uncomplicated pyelonephritis

Prostatitis, STD, travelers diarrhea, shigella

Renal elimination

SE: QT, tendon effects

Question 7

Cipro

Answer 7

2nd gen

first line for aeruginosa

Question 8

3rd gen

Answer 8

increased gram +

better than cipro with decent gram -

gemi, levo, moxi

Question 9

4th gen

Answer 9

trovaflox, alatroflox

Question 10

Acute uncomplicated cystitis

Answer 10

1. TMP-SMX
2. Nitrofurantoin
3. Fosfomycin

Question 11

Acute uncomplicated pyelonephritis

Answer 11

1. Cipro
2. Levo
3. TMP-SMX

Question 12

Complicated UTI

Answer 12

cipro or levo