Keflex (cephalexin) is an antibiotic that belongs to the cephalosporin class. It works by fighting with the bacteria in the body. Keflex is prescribed for the treatment of bacterial infections such as upper respiratory infections, ear infections, skin infections, urinary tract infections, and bone infections. Keflex is prescribed to treat infections in adults and children over the age of one year. It can be in form of syrup (Keflex syrup) or tablet (Keflex 100 mg).

Keflex Uses

This antibiotic is used to treat a wide range of bacterial infections. This antibiotic is classified as a cephalosporin. It works by preventing bacterial growth. This medication is ineffective against viral infections (such as common cold, flu). Any antibiotic's effectiveness can be reduced if it is used or misused unnecessarily.

How to use Keflex:

Take this medication orally, with or without food. Usually, it is taken every 6 to 12 hours.

Shake the bottle thoroughly before each dose if you're using the suspension. Use a measuring device to carefully measure the dose. You should not use a regular spoon because you may not get the correct dose.

The dosage is determined by your medical condition as well as your response to treatment. The dose is also weight-based in children.

Take this antibiotic at regular intervals for the best results. Even if your symptoms go away after a few days, keep taking this medication until the full prescribed amount is gone. Stopping the medication too soon may allow bacteria to grow, resulting in a recurrence of the infection.

Keflex Side Effects

  • Abdominal or stomach pain
  • Blistering
  • Peeling of the skin
  • Chills
  • Cough
  • Dark urine
  • Diarrhea
  • Dizziness
  • Fever
  • Tiredness
  • Weakness
  • Headache
  • Itching
  • Rash
  • Joint or muscle pain
  • Loss of appetite
  • Nausea
  • Vomiting


Inform your doctor if you are allergic to cephalexin, penicillins, or other cephalosporins (such as cefpodoxime), or if you have any other allergies. Some inactive ingredients present in this product may cause allergic reactions or other problems. For more information, consult your pharmacist.

Tell your doctor or pharmacist about your medical history, especially if you have kidney disease or stomach/intestinal disease, before using this medication (such as colitis).

This product's liquid form may contain sugar. If you have diabetes, proceed with caution. Inquire with your doctor or pharmacist about the safe use of this product.

During pregnancy, this medication should not be used. Discuss the risks and benefits with your doctor when you are taking this medicine during pregnancy.

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


Drug interactions can change the way your medications function or put you at risk for severe side effects. Maintain a list of all the products you use and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medications without first consulting your doctor.

This medication may interfere with certain laboratory tests (such as the Coombs' test and certain urine glucose tests), potentially resulting in false test results.


If someone has taken an overdose of this medicine and has serious symptoms such as trouble breathing, seek medical advice. Never take more than what is prescribed to you by your doctor.

Missed Dose

If you forget to take any dose or by mistake miss a dose, take it as soon as you remember it. If it is already the time for the next dose, skip the missed dose. Take your next medicine at the regular time schedule. Do not double the dose.


The medicine should not come in direct contact with heat, air, light and may damage your medicines. Exposure to medicine might cause some harmful effects or serious side effects. The medicine must be kept in a safe place and out of children’s reach.

Keflex vs Amoxicillin



Keflex (cephalexin) is an antibiotic that belongs to the cephalosporin class. Amoxicillin is a type of antibiotic. Amoxicillin belongs to a class of drugs called penicillin-like antibiotics.
This antibiotic is used to treat a wide range of bacterial infections. It is used for treating middle ear infections, strep throat, pneumonia, skin infections, and urinary tract infections. It can be taken orally or, by injection.
Keflex works by fighting bacteria in the body. Amoxicillin works by stopping the growth of bacteria in the body.

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Frequently Asked Questions

What is Keflex used for?

This antibiotic is used to treat a wide range of bacterial infections. This antibiotic is classified as a cephalosporin. It works by preventing bacterial growth. This medication is ineffective against viral infections (such as common cold, flu).

Is Keflex the same as amoxicillin?

These drugs are classified as different types of drugs. Amoxicillin is a penicillin-type antibiotic, whereas Keflex

Is Keflex penicillin?

Penicillin and Keflex (cephalexin) are antibiotics used to treat bacterial infections. Keflex and penicillin belong to separate drug classes. Penicillin is a penicillin-type antibiotic, and Keflex is a cephalosporin antibiotic.

Is Keflex a broad-spectrum antibiotic?

Keflex belongs to the antibiotic class known as cephalosporins. Keflex is a first-generation cephalosporin that works primarily against gram-positive bacteria.

Is Keflex stronger than amoxicillin?

Both antibiotics are effective against the organisms they are designed to treat when properly dosed. Cephalexin's organism coverage makes it effective in conditions where amoxicillin is ineffective, such as mastitis and bone and joint infections.

What infections does Keflex treat?

Following infections are killed by this medicine

  • Middle ear infections (otitis media)
  • Tonsillitis
  • Throat infections
  • Laryngitis
  • Bronchitis
  • Pneumonia
  • Urinary tract
  • Skin

What kind of bacteria does Keflex treat?

Keflex is used for treating respiratory tract infections caused by susceptible Streptococcus pneumoniae and Streptococcus pyogenes isolates.

How long does Keflex take to work?

Peak concentrations are reached 1 hour after dosing; however, it takes up to 48 hours for infection-related symptoms to start working.

Can Keflex treat sinus infection?

Because of inadequate antimicrobial coverage of the major organisms, penicillin, erythromycin (Suprax), and first-generation cephalosporins such as cephalexin (Keflex, Keftab) are not recommended for treating acute sinusitis.

Can I take Keflex every 4 hours?

Every day, four times: once in the morning, once around midday, once in the early afternoon, and once in the evening. These times should ideally be about 4 hours apart, such as 8 a.m., midday, 4 p.m., and 8 p.m.

Disclaimer: The information provided herein is accurate, updated and complete as per the best practices of the Company. Please note that this information should not be treated as a replacement for physical medical consultation or advice. We do not guarantee the accuracy and the completeness of the information so provided. The absence of any information and/or warning to any drug shall not be considered and assumed as an implied assurance of the Company. We do not take any responsibility for the consequences arising out of the aforementioned information and strongly recommend you for a physical consultation in case of any queries or doubts.