What side effects should I be expecting from taking Keflex?

Signs of Keflex (cephalexin) allergy: difficulty breathing, hives (rash on your body), swelling of the face, lips, tongue, or throat—If you experience any of these symptoms, please call 911 or seek emergency medical care at the nearest emergency room (ER). 

Call your doctor immediately if you experience any of the following signs:

• Signs of anemia (low red blood cell count): cold hands and feet, pale skin, lightheadedness or shortness of breath, unusual tiredness
• Signs of bleeding: unusual or easy bruising, unusual bleeding, purplish or reddish spots under your skin
• Signs of Clostridium difficile-associated diarrhea (CDAD): severe stomach pain, bloody or watery diarrhea even if these symptoms occur months after your last dose.
• Signs of liver injury: jaundice (yellowing of the skin and eyes), dark-colored urine. As with penicillins and other cephalosporins, short-term liver injury may occur.
• Signs of kidney injury: decreased urination, flank pain, and painful urination
• Seizures
• Fever
• Weakness

Common side effects of Keflex:

• Stomach pain
• Nausea, vomiting
• Indigestion
• Diarrhea
• Vaginal itching or discharge

Keflex's other side effects include headache, dizziness, confusion, and joint pain.

Keflex Overdose:  Go to the nearest emergency room or call the Poison Control Center Help Line at 1-800-222-1222. You can find more information at www.poisonhelp.org/help or your local poison control center.

Overdose symptoms: nausea, vomiting, stomach pain, diarrhea, blood in the urine.

The above list on this site may not include all the possible side effects of Keflex. Speak to your doctor or pharmacist at your local pharmacy if you have persistent side effects or any side effects that are not listed above. You can also report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088.

Source: FDA