Keflex

Keflex is a prescription medication used to treat bacterial infections. Keflex belongs to a group of drugs called cephalosporin antibiotics, which kill the bacteria that lead to infections.

This medication comes in oral (by mouth) capsule form. Keflex is taken up to 4 times a day with or without meals.

Common side effects of Keflex include upset stomach, diarrhea, and vomiting.

Keflex is a prescription medication used to treat certain bacterial infections. Keflex treats bacterial infections of the lung (pneumonia), ear, skin, bone, and urinary tract. 

Keflex and other antibiotics will not treat viral infections such as the flu or the common cold.

This medication may be prescribed for other uses.  Ask your doctor or pharmacist for more information.

Take Keflex exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

Your doctor will determine the appropriate dosage and schedule of Keflex depending on the type and severity of your bacterial infection, as well as your age.  For most infections, 250 mg of Keflex will be taken 4 times a day.  For more severe infections, 500 mg of Keflex will be taken twice a day.  The usual dosage range of Keflex is 1 to 4 grams a day, with a maximum dosage of 4 grams a day.

Serious side effects have been reported with Keflex including:

Hypersensitivity reaction:  An allergic reaction is possible with Keflex .  Tell your doctor if you are allergic to penicillin antibiotics such as amoxicillin (Moxatag) and ampicillin or cephalosporin antibiotics such as cephalexin (Keflex) and cefuroxime (Ceftin). Symptoms of an allergic reaction to Keflex include:

• skin rash
• itching
• hives
• difficulty breathing or swallowing
• sore throat
• vaginal infections
• dizziness
• fatigue
• headache
• agitation
• confusion
• hallucinations
• joint pain

Clostridium difficile associated diarrhea:  Keflex and other antibiotics can kill the “good” bacteria in the colon leading to a growth of C. difficile bacteria.  C. difficile is “bad” bacteria that can cause diarrhea.

Seizures associated with patients having poor kidney function

Common side effects of Keflex include:

• upset stomach
• diarrhea
• vomiting
• stomach cramps
• fever
• mild skin rash

This is not a complete list of Keflex side effects. Ask your doctor or pharmacist for more information.

Serious side effects have been reported with Keflex . See “Drug Precautions” section.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all the medications you take including prescription and non-prescription medications, vitamins, and herbal supplements. Especially tell your doctor if you take:

• metformin (Glucophage)
• probenecid (Benemid)

This is not a complete list of Keflex drug interactions.  Ask your doctor or pharmacist for more information.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Keflex falls into category B.  Studies in animals have failed to demonstrate a risk to the unborn baby and there are no well-controlled studies in pregnant women.

Tell your doctor if you are breastfeeding or plan to breastfeed.  The active ingredient of Keflex is excreted in human breast milk.  The effect of Keflex on the nursing infant is not known.

There is an increased risk of an allergy to Keflex for patients with a confirmed history of penicillin allergies. Know the signs and symptoms of a drug allergy (rash, hives, difficulty breathing, etc) before starting Keflex.

Keflex is commonly used to treat a wide array of infections including upper respiratory infections, ear infections, and urinary tract infections and is especially well recognized for its effectiveness in treating certain forms of cellulitis - a type of skin infection.

Your dose of Keflex may need to be adjusted if you have active kidney or liver issues or are diabetic.  Let your physician know about your full medical history before starting Keflex.