Cephalexin (Keflex®, Biocef®) is a prescription antibiotic commonly used for treating various types of bacterial infections. It can also be used to prevent heart valve infections. As with any medication, side effects are possible with cephalexin.
Some people may develop allergic reactions to cephalexin (about 10 percent of people who are allergic to penicillins may also be allergic to cephalexin). You should contact your healthcare provider immediately if you experience an unexplained rash, itchy skin, difficulty breathing, or other signs of an allergic reaction.
Other common side effects that have been seen in children and adults taking cephalexin include:
- Upset stomach (dyspepsia)
- Unexplained rash
- Yeast infection.
Some cephalexin side effects can indicate a potentially serious complication. If you experience any of these problems, stop taking the medication and contact your healthcare provider. These side effects include, but are not limited to:
- Severe or watery diarrhea
- Blood in stools
- Throat or mouth sores
- Unexplained bleeding or bruising
- Severe rash
- Difficulty breathing or swallowing
- Swelling of the throat
- Peeling of the skin.
(Click Cephalexin Side Effects and Cephalexin Precautions and Warnings to learn about other potential reactions and to find out what you should discuss with your healthcare provider before starting this medication.)