What antibiotic is safe during pregnancy in a patient with a urinary tract infection (UTI) and pyelonephritis?

From the Guidelines

For a pregnant patient with pyelonephritis, intravenous ceftriaxone is the recommended first-line antibiotic treatment, as it effectively treats common urinary pathogens, including E. coli, and has excellent penetration into renal tissue 1. When managing pyelonephritis in pregnancy, it is crucial to consider the potential risks to both the mother and the fetus. The choice of antibiotic should prioritize those that are safe in pregnancy and effective against the most common pathogens.

• Key considerations in the management of pyelonephritis in pregnancy include:
  • Prompt initiation of antibiotic therapy to prevent complications such as preterm labor, maternal sepsis, and acute kidney injury.
  • Selection of an antibiotic that is pregnancy category B, indicating no fetal risk in animal studies.
  • Choice of an antibiotic with excellent penetration into renal tissue to ensure effective treatment of the infection.
• According to the European Association of Urology guidelines, fluoroquinolones and cephalosporins are recommended for oral empiric treatment of uncomplicated pyelonephritis 1. However, for pregnant patients, cephalosporins such as ceftriaxone are preferred due to their safety profile and effectiveness.
• The recommended treatment regimen for pyelonephritis in pregnancy typically involves initial intravenous antibiotic therapy, such as ceftriaxone, until clinical improvement is observed, followed by oral antibiotics to complete a 7-14 day total course of therapy 1.
• Hospitalization is often necessary for initial management of pyelonephritis during pregnancy due to the risk of complications, and monthly urine cultures are recommended for the remainder of the pregnancy to monitor for recurrence.

From the FDA Drug Label

Pregnancy Teratogenic Effects Pregnancy Category B Cefepime was not teratogenic or embryocidal when administered during the period of organogenesis to rats at doses up to 1000 mg/kg/day (1. 6 times the recommended maximum human dose calculated on a mg/m2 basis) or to mice at doses up to 1200 mg/kg (approximately equal to the recommended maximum human dose calculated on a mg/m2 basis) or to rabbits at a dose level of 100 mg/kg (0. 3 times the recommended maximum human dose calculated on a mg/m2 basis). There are, however, no adequate and well-controlled studies of cefepime use in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Cefepime is considered safe in pregnancy, but only if clearly needed, as there are no adequate and well-controlled studies of its use in pregnant women. It falls under Pregnancy Category B. In the context of a patient with a UTI on urinalysis and history and physical examination findings of pyelonephritis, cefepime may be considered as a treatment option, given its established safety and effectiveness in treating uncomplicated and complicated urinary tract infections (including pyelonephritis) 2. However, it is crucial to weigh the benefits and risks and consider the patient's individual circumstances before making a decision.

From the Research

Antibiotic Treatment for UTI and Pyelonephritis in Pregnancy

• The use of cephalexin is recommended for pregnant women with a history of recurrent UTIs, as it reaches high bactericidal concentrations in the urinary tract and induces minimal resistance in the introital gram-negative bacterial flora 3.
• Cefazolin and ceftriaxone are also effective in treating pyelonephritis in pregnancy, with a 10-day course of oral cephalexin being a common treatment regimen 4.
• Outpatient antibiotic therapy with ceftriaxone and cephalexin is effective and safe in selected pregnant women with pyelonephritis 4.
• The choice of antibiotic should consider antimicrobial resistance patterns in the local community, and there is a need to balance efficacy, patient acceptance, and safety for the developing fetus 5.
• A short 7-day treatment with third-generation cephalosporins, such as ceftriaxone and cefixime, may be effective in treating acute pyelonephritis in young women, including those who are pregnant 6.
• Cephalosporins, including cephalexin, are excreted primarily by the kidney and achieve high urinary concentrations, making them suitable for treating urinary tract infections 7.

Suitable Antibiotics

• Cephalexin
• Cefazolin
• Ceftriaxone
• Cefixime

Important Considerations

• Antimicrobial resistance patterns in the local community should be considered when choosing an antibiotic 5.
• The treatment regimen should be effective, safe, and well-tolerated by the pregnant woman 4, 5.
• Outpatient antibiotic therapy may be suitable for selected pregnant women with pyelonephritis, but inpatient treatment may be necessary in some cases 4, 5.