Dosage for cephalexin may vary based on the condition it’s being used to treat. The typical dosage for most of the bacterial infections it treats is 250 milligrams (mg) every 6 hours. Cephalexin comes as an oral tablet, capsule, and suspension. It’s important to take the cephalexin dosage your doctor prescribes.

Cephalexin is used in adults and certain children to treat bacterial infections such as:

Cephalexin belongs to a drug class called antibiotics. Cephalexin isn’t available in a brand-name version. A brand-name version called Keflex used to be available but has been discontinued.

This article describes the dosage(s) of cephalexin, its strengths, and how to take it. For a detailed overview of this drug, check out this in-depth cephalexin article.

To learn more about these warnings, talk with your doctor.

Your doctor will likely start you on a low dosage and adjust it over time to reach the right amount for you. They’ll ultimately prescribe the smallest dosage that provides the desired effect.

The following information describes dosages that are commonly used or recommended for cephalexin. But be sure to take the dosage your doctor prescribes for you. They’ll determine the best dosage to fit your needs. In some cases, doctors may adjust your dosage from those mentioned here.

Cephalexin forms

Cephalexin comes in three forms:

  • oral capsule
  • oral tablet
  • powder for oral suspension

Cephalexin strengths

Cephalexin oral capsule and tablet come in three strengths:

  • 250 milligrams (mg)
  • 500 mg
  • 750 mg

Cephalexin powder for oral suspension comes in two strengths:

  • 125 mg per 5 milliliters (mL)
  • 250 mg per 5 mL

Cephalexin is approved to treat the following bacterial infections:

  • respiratory tract infections
  • otitis media (middle ear infections)
  • skin and skin structure infections
  • bone infections
  • genitourinary (urinary tract) infections

The typical cephalexin dosage for adults with these types of bacterial infections is 250 mg taken every 6 hours, or a dose of 500 mg every 12 hours may be given.

If you have a severe infection, your doctor may prescribe a larger dose, up to 4 grams per day, taken in divided doses.

Always follow your doctor’s instructions. Notify them if you experience any side effects that may prevent you from taking your medication.

Cephalexin is used to help treat the following bacterial infections in children:

  • respiratory tract infections
  • otitis media (middle ear infections)
  • skin and skin structure infections
  • bone infections
  • genitourinary (urinary tract) infections

The dosage for children ages 15 to 17 years old is the same as the dosage for adults: 250 mg taken every 6 hours, or a dose of 500 mg every 12 hours may be given. If the child has a severe infection, their doctor may prescribe a larger dose, up to 4 grams per day, taken in divided doses.

The dosage for respiratory tract, skin, bone, and geniotourinary infections in children ages 1 to 14 years old is typically 25 to 50 mg per kilogram (kg) of body weight per day taken in divided doses. A child’s doctor may double their dose for severe infections.

The dosage for otitis media in children ages 1 to 14 years old is 75 to 100 mg/kg of body weight per day, given in equally divided doses every 6 hours.

For more information about cephalexin’s dosage for children, talk with your child’s doctor or a pharmacist.

Your doctor or pharmacist will give you specific instructions for taking cephalexin. They’ll typically include the following:

  • Cephalexin can be taken with or without food.
  • You should take cephalexin at the same time each day. Cephalexin may not work as well or may stop working completely if you miss doses or don’t take the drug on schedule. For this drug to work well, a certain amount needs to be in your body at all times.

How long do you take cephalexin?

Cephalexin is typically prescribed for a limited time. Your doctor will determine your individual treatment plan, including how long you’ll take cephalexin.

Be sure to take cephalexin as prescribed. If you don’t finish your course of treatment with this drug, your infection may not improve and may potentially worsen.

The following are answers to some commonly asked questions about cephalexin’s dosage.

How many days do you need to take cephalexin?

The length of time you’ll need to take cephalexin for will vary depending on what condition it’s being used to treat. You’ll typically need to take it for 7 to 14 days.

Let your doctor know whether you don’t start to feel better after taking cefalexin for 2 to 3 days or whether you feel worse at any time. Do not stop taking it before you’re supposed to, even if you’re already feeling better. Stopping cephalexin early could increase the risk of the infection worsening or coming back.

Is 3 days of cephalexin enough for a UTI?

Cephalexin is typically prescribed for 7 to 14 days. Although you may start to notice relief from urinary tract infection (UTI) symptoms after 2 or 3 days, it’s important to finish your full course of cephalexin.

If you have additional questions about how long you need to take cephalexin for UTI, talk to your doctor. They can provide you with personalized information.

Do not take more cephalexin than your doctor prescribes, as this can lead to harmful effects.

Symptoms of cephalexin overdose

Symptoms caused by an overdose of cephalexin can include:

What to do in case you take too much cephalexin

Call your doctor right away if you think you’ve taken too much cephalexin. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.