Pharm - UTI Flashcards
What are the goals of therapy for UTI?
- Eradicate invading organism
- Prevent/treat systemic consequences of infection
- Decrease the potential for collateral damage with too broad of antimicrobial therapy.
What is the most common pathogens for acute cystitis?
E. coli
*can also be enterobacteriaceae (proteus mirabilis and K. pneumonia) and staph saprophyticus
What is the most common pathogens for pyelonephritis?
E. coli, enterobacteriaceae, and enterococcus.
What are the advantages of prescribing phenazopyridine (pyridium)?
It relieves symptoms caused by irritation of the urinary tract such as pain, burning, and feeling of needing to urinate urgently or frequently.
It is basically a painkiller to soothe lining of urinary tract.
What is the role of vaginal estrogen in prevention of cystitis?
normalizes vaginal flora, supporta vaginal growth of lactobacillus spp.
Appears to reduce risk of reoccurence.
What is the role of cranberry in prevention of cystitis?
Prevents bacterial adherence to uroepithelial cells.
What is the role of lactobacillus in prevention of cystitis?
competitive exclusion of usual uropathogens.
MOA of nitrofurantoin (Macrobid)
Converted by bacteria to metabolites that inhibit bacterial ribosomes - preventing protein synthesis.
Given patient CrCl > 60 mL/min, is there a contraindication to nitrofurantoin (Macrobid)?
No, no adjustments in dosing are needed.
Given patient CrCl < 60 mL/min, is there a contraindication to nitrofurantoin (Macrobid)?
The manufacturer suggests not using, but data suggest safe and effective with CrCl down to 30 mL/min.
Given patient CrCl < 30 mL/ in, is there a contraindication to nitrofurantoin (Macrobid)?
Yes, avoid drug.
Nitrofurantoin (Macrobid) ADR
MC - urine turns brown, nausea, HA, flatulence.
- can cause hemolytic anemia with G6PD deficiency
- up to 1% serious ADR is acute or chronic pulmonary reaction including fibrosis and hemorrhage
Acute pulmonary reaction to nitrofurantoin (Macrobid)
- hypersensitivity type I or II
- appears in days
- fever, dyspnea, irritating cough, rash, chest pain, cyanosis
Chronic pulmonary reaction to nitrofurantoin (Macrobid)
- either cell-mediated or toxic response
- develops in several months
- dyspnea, dry cough, fatigue, less intense than acute
Duration of therapy for nitrofurantoin (Macrobid) for uncomplicated UTI
5 days
Duration of therapy for TMP/SMX (Bactrim) for uncomplicated UTI
3 days
Duration of therapy for fosfomycin for uncomplicated UTI
1 day
Contraindications to use of TMP/SMX (Bactrim)
- 3rd trimester of pregnancy d/t risk of kernicterus in newborn
- avoid if prevalence of resistance > 20% or if patient has taken Bactrim for cystitis in the preceding 3 months
ADR of TMP/SMX (Bactrim)
- rash
- allergic reaction
- GI intolerance
- bone marrow suppression
Indications for fosfomycin
- tx of uncomplicated cystitis
- may be useful for complicated lower tract infections as well
- NOT effective for systemic infections
- lower rates of collateral damage but is expensive
- covers most pathogens
Contraindications to use of fosfomycin
Avoid if suspicion for early pyelonephritis
ADR d/t fosfomycin
Mild GI - diarrhea, nausea
What is the role of fluoroquinolone in the treatment of cystitis?
- used for both cystitis and systemic infections
- levofloxacin (Levaquin) and ciprofloxacin (Cipro)
- good gram-negative activity, some gram-positive activity (active against pseudomonas)
What population do you NOT use fluoroquinolone in?
Do NOT use in children or pregnancy.
*limit use with UTI’s as to preserve use for more serious infections
What is the collateral damage caused by fluoroquinolone?
D/t excellent systemic concentrations and broad-spectrum nature, fluoroquinolone causes A LOT of collateral damage.
ADR of fluoroquinolone
- QT prolongation
- GI intolerance
- tendon rupture (especially in the elderly)
What is the place in therapy for PO beta lactams in tx of cystitis?
They are less effective than fluoroquinolone or Bactrim d/t high resistance rates, so they should only be used it the bacteria has known susceptibility.
Examples: augmentin, cefdinir, and cephalexin.
Given a patient with uncomplicated, acute cystitis, select the most appropriate antibiotic.
1st line agents: nitrofurantoin (Macrobid)*, TMP-SMX (Bactrim), or fosfomycin
nitrofurantoin (Macrobid) vs. TMP-SMX (Bactrim)
Macrobid is 1st line tx and prophylaxis of uncomplicated cystitis
- It has equal efficacy as Bactrim with less potential for collateral damage (it concentrates in the urine, so doesn’t have large effects on bacteria elsewhere)
- low resistance rates
- inexpensive
Choose the best abx therapy for continuous prophylaxis for recurrent UTIs
- patients given daily continuous abx tx for 6 months, then d/x
- if recurrence does not decrease the therapy will be reinitiated
- can use Bactrim, TMP-SMX, Macrobid, or Cipro
Risk factors for MDR organisms in complicated UTI
- inpatient stay
- recent use of fluoroquinolone, TMP-SMX, or broad-spectrum beta-lactam
- international travel to areas with high resistance
What is the place in therapy of fluoroquinolone in tx of complicated UTI?
It is the drug of choice if no contraindications, h/o allergy, drug interaction that can’t be modified, or h/o fluoroquinolone use in the past 3 months with high risk of resistance.
What is the appropriate abx regimen for outpatient treatment of complicated UTI?
*drug of choice: fluoroquinolone
If there is fluoroquinolone resistance in outpatient tx of complicated UTI, what regimen do you use?
use long-acting IV or IM abx
- ceftriaxone IV/IM + fluoroquinolone PO
- gentamicin or tobramycin IV/IM + PO fluoroquinolone
- ertapenem IV one time + PO fluoroquinolone
If no MDR gram-negative infection in outpatient tx of complicated UTI…
- treat with standard spectrum abx until C&S is back
- ceftriaxone, fluoroquinolone
- tailor the abx when results are available
- treat IV until patient improves, then oral based on C&S
- duration: 5-14 days, based on response
If risk for MDR gram-negative in outpatient tx of complicated UTI…
- use broad-spectrum abx with ESBL coverage (imipenem or meropenem)
- if urine gram stain shows gram-positive cocci add one:
- vancomycin, daptomycin, or linezolid
