Urinary Tract Infections in Pregnancy Medication

Updated: Jul 13, 2023
  • Author: Raisa O Platte, MD, PhD; Chief Editor: Edward David Kim, MD, FACS  more...
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Medication Summary

The goals of pharmacotherapy are to eradicate the infection, reduce morbidity, and prevent complications. Agents used include antibiotics and analgesics.



Nitrofurantoin (Furadantin, Macrobid, Macrodantin)

Nitrofurantoin is a synthetic nitrofuran that interferes with bacterial carbohydrate metabolism by inhibiting acetylcoenzyme A. It is bacteriostatic at low concentrations (5-10 mcg/mL) and bactericidal at higher concentrations. It is bactericidal against uropathogens such as Staphylococcus saprophyticus, Enterococcus faecalis, and Escherichia coli; it possesses no activity against Proteus, Serratia, or Pseudomonas species. It received a “A-I”  rating in the 2011 IDSA guidelines for treating UTIs.

It is manufactured in different forms to facilitate durable urine concentrations: macrocrystals (Macrodantin), microcrystal suspension (Furadantin), and a combined preparation (Macrobid). This agent achieves no appreciable concentrations in the prostate, kidney, or blood. Administer 100 mg orally twice daily for 5-7 days.

Cephalexin (Keflex)

This is a first-generation cephalosporin that inhibits bacterial growth by inhibiting bacterial cell wall synthesis. It is bactericidal and effective against rapidly growing organisms forming cell walls. Administer 500 mg orally every six hours for 5-7 days. 

Amoxicillin and clavulanate (Augmentin, Amoclan)

Amoxicillin interferes with the synthesis of cell wall mucopeptides during active multiplication, resulting in bactericidal activity against susceptible bacteria. This drug combination treats bacteria normally resistant to beta-lactam antibiotics. Administer 500/125 mg orally every 8 hours for 5-7 days. An alternative dosing is 875/125 mg twice daily for 5-7 days.

Amoxicillin (Moxatag)

Amoxicillin interferes with synthesis of cell wall mucopeptides during active multiplication, resulting in bactericidal activity against susceptible bacteria. Administer 500 mg orally every eight hours for 5-7 days. This should not be used for empiric treatment given its poor efficacy.

Cefuroxime (Ceftin, Zinacef)

Cefuroxime is a second-generation cephalosporin that maintains the gram-positive activity of first-generation cephalosporins; it adds activity against Proteus mirabilis, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, and Moraxella catarrhalis. Administer 250 mg orally twice daily for 3-7 days

Fosfomycin (Monurol)

Fosfomycin was given a "B, I" rating in the 1999 IDSA guidelines for treating UTIs. Phosphonic acid is a bactericidal agent active against most UTI pathogens, including Escherichia coli and Enterobacter, Klebsiella, and Enterococcus species. Little cross-resistance between fosfomycin and other antibacterial agents exists. It is primarily excreted unchanged in the urine, and concentrations remain high for 24-48 hours after a single dose. It is unique but quite expensive. Administer 3 g orally as single dose with 3-4 oz of water

Ceftriaxone (Rocephin (DSC))

Ceftriaxone is a third-generation cephalosporin with broad-spectrum gram-negative activity; has lower efficacy against gram-positive organisms but higher efficacy against resistant organisms; highly stable in presence of beta-lactamases (penicillinase and cephalosporinase) of gram-negative and gram-positive bacteria. Administer 1-2 g IV once a day for acute uncomplicated pyelonephritis.

Ertapenem (Invanz)

Ertapenem is a carbapenem that inhibits cell-wall synthesis by binding to penicillin-binding proteins; resistant to most beta-lactamases. Indicated for complicated urinary tract infections, including pyelonephritis. Administer 1 g/day IV/IM for up to 14 days; after ≥3 days of parenteral therapy, patients may be switched to appropriate PO regimen if they have shown clinical improvement.