Keflex

DRUG DESCRIPTION

Keflex® Capsules (Cephalexin, USP) is a semisynthetic cephalosporin antibiotic intended for oral administration. It is 7-(D-a-Amino-a-phenylacetamido)-3-methyl-3-cephem-4-carboxylic acid monohydrate. Cephalexin has the molecular formula C16H17N3O4S•H2O and the molecular weight is 365.41.

Cephalexin has the following structural formula:

KEFLEX® (Cephalexin) Structural Formula Illustration

The nucleus of cephalexin is related to that of other cephalosporin antibiotics. The compound is a zwitterion; i.e., the molecule contains both a basic and an acidic group. The isoelectric point of cephalexin in water is approximately 4.5 to 5. The crystalline form of cephalexin which is available is a monohydrate. It is a white crystalline solid having a bitter taste. Solubility in water is low at room temperature; 1 or 2 mg/mL may be dissolved readily, but higher concentrations are obtained with increasing difficulty.

The cephalosporins differ from penicillins in the structure of the bicyclic ring system. Cephalexin has a D-phenylglycyl group as substituent at the 7-amino position and an unsubstituted methyl group at the 3-position.

Each capsule contains cephalexin monohydrate equivalent to 250 mg, 333 mg, 500 mg or 750 mg of cephalexin. The capsules also contain cellulose, D & C Yellow No. 10, F D & C Blue No. 1, F D & C Yellow No. 6, gelatin, magnesium stearate, silicone, titanium dioxide, and other inactive ingredients.

What are the possible side effects of cephalexin (Keflex, Panixine)?

Get 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;
  • seizure (convulsions);
  • 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,...

Read All Potential Side Effects and See Pictures of Keflex »

What are the precautions when taking cephalexin (Keflex)?

Before taking cephalexin, tell your doctor or pharmacist if you are allergic to it; or to penicillins or other cephalosporins (such as cefpodoxime); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, stomach/intestinal disease (such as colitis).

The liquid form of this product may contain sugar. Caution is advised if you have diabetes. Ask your doctor or pharmacist about using this product safely.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription...

Read All Potential Precautions of Keflex »


Keflex Consumer (continued)

SIDE EFFECTS: Diarrhea may occur. If diarrhea persists or worsens, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Do not use anti-diarrhea products or narcotic pain medications if you have any of the following symptoms because these products may make them worse. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

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

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking cephalexin, tell your doctor or pharmacist if you are allergic to it; or to penicillins or other cephalosporins (such as cefpodoxime); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, stomach/intestinal disease (such as colitis).

The liquid form of this product may contain sugar. Caution is advised if you have diabetes. Ask your doctor or pharmacist about using this product safely.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication passes into breast milk. Consult your doctor before breast-feeding.


Keflex Patient Information Including Side Effects

Brand Names: Keflex, Panixine

Generic Name: cephalexin (Pronunciation: sef a LEX in)

  • What is cephalexin (Keflex)?
  • What are the possible side effects of cephalexin (Keflex)?
  • What is the most important information I should know about cephalexin (Keflex)?
  • What should I discuss with my healthcare provider before taking cephalexin (Keflex)?
  • How should I take cephalexin (Keflex)?
  • What happens if I miss a dose (Keflex)?
  • What happens if I overdose (Keflex)?
  • What should I avoid while taking cephalexin (Keflex)?
  • What other drugs will affect cephalexin (Keflex)?
  • Where can I get more information?

What is cephalexin (Keflex)?

Cephalexin is in a group of drugs called cephalosporin antibiotics. Cephalexin fights bacteria in the body.

Cephalexin is used to treat infections caused by bacteria, including upper respiratory infections, ear infections, skin infections, and urinary tract infections.

Cephalexin may also be used for other purposes not listed in this medication guide.

What are the possible side effects of cephalexin (Keflex)?

Get 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;
  • seizure (convulsions);
  • 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. You may report side effects to FDA at 1-800-FDA-1088.

What is the most important information I should know about cephalexin (Keflex)?

Do not use this medication if you are allergic to cephalexin, or to similar antibiotics, such as Ceclor, Ceftin, Cefzil, Duricef, Fortaz, Omnicef, Spectracef, Suprax, and others.

Before using cephalexin, 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. Cephalexin will not treat a viral infection such as the common cold or flu.

Related Drug Centers
  • Keflex


Related Drugs Index: