Generic Name: cephalexin (sef a LEX in)
Brand Names: Keflex, Panixine
What is Keflex?
Keflex is in a group of drugs called cephalosporin antibiotics. Keflex fights bacteria in the body.
Keflex is used to treat infections caused by bacteria, including upper respiratory infections, ear infections, skin infections, and urinary tract infections.
Keflex may also be used for other purposes not listed in this medication guide.
What is the most important information I should know about Keflex?Do not use Keflex if you are allergic to cephalexin, or to similar antibiotics, such as Ceclor, Ceftin, Cefzil, Duricef, Fortaz, Omnicef, Spectracef, Suprax, and others.
Before using Keflex, tell your doctor if you are allergic to any drugs (especially penicillins), or if you have kidney or liver disease, a stomach or intestinal disorder such as colitis, diabetes, or if you are malnourished.Take this medication for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated. Keflex will not treat a viral infection such as the common cold or flu.
What should I discuss with my healthcare provider before taking Keflex?Do not use Keflex if you are allergic to cephalexin, or to other cephalosporin antibiotics, such as:
ceftazidime (Fortaz); or
Before using Keflex, tell your doctor if you are allergic to any drugs (especially penicillins), or if you have:
a stomach or intestinal disorder such as colitis;
if you are malnourished.
If you have any of these conditions, you may need a dose adjustment or special tests to safely take Keflex.
The oral suspension (liquid) form of Keflex may contain sugar. This may affect you if you have diabetes.FDA pregnancy category B. Keflex is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Cephalexin can pass into breast milk and may harm a nursing baby. Do not use Keflex without telling your doctor if you are breast-feeding a baby.
How should I take Keflex?
Take the medication exactly as it was prescribed for you. Do not use the medication in larger amounts, or use it for longer than recommended by your doctor. Follow the instructions on your prescription label.Take Keflex with a full glass of water.
Dissolve the Keflex dispersible tablet in a small amount of water, about 2 teaspoonfuls. Stir this mixture and drink all of it right away. To make sure you get the entire dose, add a little more water to the same glass, swirl gently and drink right away. Do not swallow or chew a dispersible tablet.Shake the oral suspension (liquid) well just before you measure a dose. To be sure you get the correct dose, measure the liquid with a marked measuring spoon or medicine cup, not with a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one. Take Keflex for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated. Keflex will not treat a viral infection such as the common cold or flu.
This medication can cause you to have unusual results with certain medical tests. Tell any doctor who treats you that you are using Keflex.Store the tablets and capsules at room temperature away from moisture and heat. Store the liquid medicine in the refrigerator. Throw away any unused medication after 14 days.
What happens if I miss a dose?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at your next regularly scheduled time. Do not take extra medicine to make up the missed dose.
What happens if I overdose?Seek emergency medical attention if you think you have used too much of this medicine.
Overdose symptoms may include nausea, vomiting, stomach pain, diarrhea, and blood in your urine.
What should I avoid while taking Keflex?
Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or has blood in it, call your doctor. Do not use any medicine to stop the diarrhea unless your doctor has told you to.
Keflex side effectsGet emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have any of these serious side effects:
diarrhea that is watery or bloody;
fever, sore throat, and headache with a severe blistering, peeling, and red skin rash;
pale or yellowed skin, dark colored urine, fever, confusion or weakness;
easy bruising or bleeding, unusual weakness;
confusion, agitation, hallucinations (seeing things that are not there); or
urinating less than usual or not at all.
Less serious side effects may include:
mild nausea, vomiting, diarrhea;
dizziness, tired feeling;
joint pain; or
vaginal itching or discharge.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Keflex side effects (in more detail)
What other drugs will affect Keflex?
Before using Keflex, tell your doctor if you are using any of the following drugs:
a blood thinner such as warfarin (Coumadin);
metformin (Fortamet, Glucophage, Riomet, Actoplus, Avandamet, Metaglip); or
This list is not complete and there may be other drugs that can interact with Keflex. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.
More Keflex resources
- Keflex Prescribing Information (FDA)
- Keflex Advanced Consumer (Micromedex) - Includes Dosage Information
- Keflex Monograph (AHFS DI)
- Keflex MedFacts Consumer Leaflet (Wolters Kluwer)
- cephalexin MedFacts Consumer Leaflet (Wolters Kluwer)
- Cephalexin Prescribing Information (FDA)
- Cephalexin Professional Patient Advice (Wolters Kluwer)
- Panixine Prescribing Information (FDA)
Compare Keflex with other medications
Where can I get more information?
- Your pharmacist can provide more information about Keflex.
- Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Keflex only for the indication prescribed.
- Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.