What is cefalexin?

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Generic Name: Cefalexin Brand Name(s): Generics only. No brands available.

Know the basics

What is cefalexin used for?

Cefalexin, also known as cephalexin, is used to treat a wide variety of bacterial infections. This medication belongs to a antibiotic drug class known as cephalosporins. It works by stopping the growth of bacteria.

Antibiotics such as cefalexin will not work for viral infections such as colds and flu. Taking antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment. Please take only as instructed by your doctor.

Cefalexin may also be used before dental procedures in patients with certain heart conditions (such as artificial heart valves) to help prevent serious infection of the heart (bacterial endocarditis).

How should I take cefalexin?

Follow medication guide provided by your doctor or pharmacist before you start using this medication. If you have any questions, ask your doctor or pharmacist. Take this medication by mouth as directed by your doctor, usually every 6 to 12 hours with or without food.

If you are using the suspension, shake the bottle well before each dose. Measure the dose carefully using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.

The dosage is based on your medical condition and response to treatment. In children, the dose is also based on weight.

Antibiotics work best when the amount of medicine in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals.

Continue to take this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may allow bacteria to continue to grow, which may result in a return of the infection.

Tell your doctor if your condition persists or worsens.

How do I store cefalexin?

Cefalexin is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store cefalexin in the bathroom or the freezer. There may be different brands of cefalexin that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush cefalexin down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Know the precautions & warnings

What should I know before using cefalexin?

Do not use this medication if you are allergic to cephalexin, or to other cephalosporin antibiotics, such as:

  • cefaclor (Ceclor); cefadroxil (Duricef); cefdinir (Omnicef); cefditoren (Spectracef); cefixime (Suprax); cefprozil (Cefzil); ceftazidime (Fortaz); cefuroxime (Ceftin).

Before using cephalexin, tell your doctor if you are allergic to any drugs (especially penicillins), or if you have:

  • Kidney disease;
  • Liver disease;
  • A stomach or intestinal disorder such as colitis;
  • Diabetes; or
  • If you are malnourished.

If you have any of these conditions, you may need a dose adjustment or special tests to safely take cephalexin.

The oral suspension (liquid) form of cephalexin may contain sugar. This may affect you if you have diabetes.

Is it safe to take cefalexin during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this medication during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this medication. This medication is pregnancy risk category B according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown.

Know the side effects

What are the side effects of cefalexin?

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);
  • urinating less than usual or not at all.

Less serious side effects may include:

  • mild nausea, vomiting, diarrhea;
  • dizziness, tired feeling;
  • joint pain;
  • vaginal itching or discharge.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Know the interactions

What drugs may interact with cefalexin?

Cefalexin may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, non-prescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Cholestyramine, Metformin.

Does food or alcohol interact with cefalexin?

Cefalexin may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with cefalexin?

Cefalexin may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:

  • Colitis (inflammation in gut)
  • Diarrhea, severe, history of—Use with caution. May make these conditions worse.
  • Kidney disease—Use with caution. Effects may be increased because of slower removal of the medicine from the body.

Understand the dosage

The information provided is not a substitute for medical advice. ALWAYS consult your doctor or pharmacist before using this medication.

What is the dose of cefalexin for an adult?

Usual Adult Dose for Bacterial Endocarditis Prophylaxis

2 g orally as a single dose one hour before the procedure

Usual Adult Dose for Cystitis

250 mg orally every 6 hours or 500 mg orally every 12 hours for 7 to 14 days

Usual Adult Dose for Otitis Media

500 mg orally every 6 hours for 10 to 14 days

Usual Adult Dose for Pharyngitis

250 mg orally every 6 hours or 500 mg orally every 12 hours

Usual Adult Dose for Skin or Soft Tissue Infection

250 mg orally every 6 hours or 500 mg orally every 12 hours

Usual Adult Dose for Osteomyelitis

500 mg orally every 6 hours
Therapy should be continued for approximately 4 to 6 weeks, depending on the nature and severity of the infection. Chronic osteomyelitis may require an additional one to two months of antibiotic therapy and may benefit from surgical debridement.

Usual Adult Dose for Prostatitis

500 mg orally every 6 hours for 14 days

Usual Adult Dose for Pyelonephritis

500 mg orally every 6 hours for 14 days

Usual Adult Dose for Upper Respiratory Tract Infection

250 to 500 mg orally every 6 hours for 7 to 10 days

Usual Adult Dose for Bacterial Infection

250 to 500 mg orally every 6 hours
Therapy should be continued for approximately 7 to 21 days, depending on the nature and severity of the infection.

What is the dose of Cefalexin for a child?

Usual Pediatric Dose for Otitis Media

12.5 to 25 mg/kg orally every 6 hours

Usual Pediatric Dose for Pharyngitis

Over 1 year of age:
Streptococcal pharyngitis: 12.5 to 25 mg/kg orally every 12 hours

Usual Pediatric Dose for Skin or Soft Tissue Infection

12.5 to 25 mg/kg orally every 12 hours

Usual Pediatric Dose for Bacterial Endocarditis Prophylaxis

As an alternative in penicillin-allergic patients (non-anaphylactoid type): 50 mg/kg (maximum 2 g) orally once, 1 hour before procedure

How is cefalexin available?

Cefalexin is available in the following dosage forms and strengths:

  • Tablet, oral: 250mg, 500mg;
  • Capsule, oral: 250mg, 500mg, 750mg;
  • Powder for Suspension, reconstitution, oral: 125mg/5ml, 250mg/5ml.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of cefalexin , take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Sources

Review Date: January 4, 2017 | Last Modified: January 4, 2017

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