Is cephalexin (Keflex) safe during pregnancy?

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Last updated: March 10, 2025 • View editorial policy

From the FDA Drug Label

Pregnancy Teratogenic Effects Pregnancy category B Reproduction studies have been performed on mice and rats using oral doses of cephalexin monohydrate 0.6 and 1. 5 times the maximum daily human dose (66 mg/kg/day) based upon mg/m2, and have revealed no harm to the fetus. There are, however, no adequate and well-controlled studies 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

Cephalexin (Keflex) is classified as Pregnancy Category B, which means that reproduction studies in animals have shown no harm to the fetus, but there are no adequate and well-controlled studies in pregnant women. It should be used during pregnancy only if clearly needed 1.

From the Research

Keflex (cephalexin) is generally considered safe during pregnancy, as it belongs to the cephalosporin class of antibiotics, which have a good safety profile during pregnancy 2, 3. When considering the use of Keflex during pregnancy, it is essential to weigh the potential benefits against the risks. The medication is often prescribed to treat urinary tract infections, skin infections, and respiratory infections when necessary.

  • The typical adult dosage is 250-500 mg taken orally every 6 hours, or 500-1000 mg every 12 hours, depending on the severity of the infection.
  • Treatment usually lasts 7-14 days.
  • Keflex works by inhibiting bacterial cell wall synthesis. It is crucial to note that while Keflex is considered safe, it should only be used when the potential benefits outweigh the risks, as with any medication during pregnancy 4, 3.
  • Always take the full course of antibiotics as prescribed, even if symptoms improve before completion.
  • If you experience severe side effects like rash, itching, or difficulty breathing, contact your healthcare provider immediately.
  • Before taking Keflex during pregnancy, inform your doctor about any allergies to cephalosporins or penicillins and any other medications you are taking 2, 3. The most recent and highest quality study 3 supports the use of β-lactams, such as cephalexin, as the preferred treatment for many common infections in pregnancy, including urinary tract infections, pelvic inflammatory disease, and upper- and lower-respiratory-tract infections.

References

Research

A Review of Antibiotic Use in Pregnancy.

Pharmacotherapy, 2015

Research

Antibacterial agents in pregnancy.

Infectious disease clinics of North America, 1995

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.