Cephalexin
Keflex (cephalexin) is a first-generation cephalosporin antibiotic used to treat a variety of bacterial infections including respiratory tract infections, skin infections, ear infections, and urinary tract infections. It works by preventing bacteria from forming cell walls, which is essential for their survival. This medication is typically prescribed for adults and children when bacterial infections are confirmed or strongly suspected.
Keflex is a commonly prescribed antibiotic used to treat various bacterial infections by killing or stopping the growth of bacteria.
Key facts at a glance
- RxNorm
- 203167
- Generic
- Keflex
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Keflex is used to treat respiratory tract infections (such as pneumonia and bronchitis), skin and soft tissue infections, bone and joint infections, ear infections, and urinary tract infections. It may also be prescribed for dental infections and as preventive therapy before certain surgical procedures.
As a first-generation cephalosporin, Keflex works by interfering with bacteria's ability to form cell walls. It binds to specific proteins in the bacterial cell membrane and inhibits the synthesis of peptidoglycan, a critical component of the cell wall, ultimately causing bacterial death.
Keflex should be taken exactly as prescribed and completed in full even if symptoms improve. Patients with penicillin allergies may have cross-reactivity and should inform their doctor. Common side effects include diarrhea, nausea, and stomach upset. Severe allergic reactions, persistent diarrhea, or new signs of infection should be reported to a healthcare provider immediately.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy