Brand Name(s):

  • Keflex®Pulvules®

WHY is this medicine prescribed?

Cephalexin is a cephalosporin antibiotic used to treat certain infections caused by bacteria such as pneumonia and bone, ear, skin, and urinary tract infections. Antibiotics will not work for colds, flu, or other viral infections.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

HOW should this medicine be used?

Cephalexin comes as a capsule, tablet, and liquid to take by mouth. It is usually taken every 6 hours (four times a day) or every 12 hours (twice a day) for 7-10 days. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take cephalexin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Shake the liquid well before each use to mix the medication evenly.

The capsules and tablets should be swallowed whole and taken with a full glass of water.

Continue to take cephalexin even if you feel well. Do not stop taking cephalexin without talking to your doctor.

What SPECIAL PRECAUTIONS should I follow?

Before taking cephalexin,

  • tell your doctor and pharmacist if you are allergic to cephalexin or any other cephalosporin antibiotic such as cefadroxil (Duricef) or cephradine (Velosef), penicillin, or any other drugs.
  • tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially other antibiotics, anticoagulants ('blood thinners') such as warfarin (Coumadin), probenecid (Benemid), and vitamins.
  • tell your doctor if you have or have ever had kidney or liver disease, colitis, or stomach problems.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking cephalexin, call your doctor.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking cephalexin.

What SPECIAL DIETARY instructions should I follow?

Cephalexin may cause an upset stomach. Take cephalexin with food or milk.

What should I do IF I FORGET to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Cephalexin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • upset stomach
  • diarrhea
  • vomiting
  • mild skin rash

If you experience any of the following symptoms, call your doctor immediately:

  • severe skin rash
  • itching
  • hives
  • difficulty breathing or swallowing
  • wheezing
  • unusual bleeding or bruising
  • sore throat
  • painful mouth or throat sores
  • vaginal infection

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store the capsules and tablets at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Keep liquid medicine in the refrigerator, tightly closed, and throw away any unused medication after 14 days. Do not freeze. Talk to your pharmacist about the proper disposal of your medication.

What should I do in case of OVERDOSE?

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to cephalexin.

If you are diabetic, use Clinistix or TesTape (not Clinitest) to test your urine for sugar while taking this drug.

Do not let anyone else take your medication. Your prescription is probably not refillable. If you still have symptoms of infection after you finish the cephalexin, call your doctor.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Last Reviewed: September 1, 2010.