Key takeaways
- Cephalexin is a generic antibiotic used to treat certain bacterial infections, including urinary tract infections (UTIs), skin infections, respiratory tract infections, ear infections, and bone infections.
- For adults and children ages 15 years and older, typical cephalexin dosages are 250 milligrams (mg) every 6 hours or 500 mg every 12 hours for 7 to 14 days. For children younger than 15 years, doctors calculate dosages based on body weight.
- Cephalexin comes in tablets, capsules, and liquid suspension forms in various strengths. If you have kidney problems, your doctor may adjust your dosage.
Cephalexin is used to treat certain bacterial infections in adults and some children. Examples of infections doctors may prescribe cephalexin to treat include:
This medication is swallowed, usually two or four times a day, depending on your dosage. The information below describes commonly prescribed cephalexin dosages.
If you want to know more about cephalexin oral forms, see this cephalexin overview article. It covers details about the drug’s uses, side effects, ways to save on cost, and more.
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Forms and strengths of cephalexin
Cephalexin oral forms come as:
- Tablets that you’ll swallow. These are available in strengths of:
- 250 milligrams (mg)
- 500 mg
- Capsules that you’ll swallow. These are available in strengths of:
- 250 mg
- 500 mg
- Liquid suspension that you’ll swallow. (This comes as a powder that’s mixed into a liquid mixture by a pharmacist.) It’s available in strengths of:
- 125 mg per 5 milliliters (mL)
- 250 mg per 5 mL
Cephalexin dosage
The drugmaker provides recommended cephalexin dosages, but your doctor will ultimately determine the dosage that’s best for you. Do not change your dosage of cephalexin oral forms without your doctor’s recommendation.
Usual recommended dosages of cephalexin
For certain bacterial infections in adults and children ages 15 years and older, cephalexin’s recommended dosages are:
- 250 milligrams (mg) once every 6 hours for 7 to 14 days, or
- 500 mg once every 12 hours for 7 to 14 days
For severe infections, doctors may increase the dosage to 4 grams (g), divided into two or four doses per day.
Pediatric dosages of cephalexin
Oral cephalexin is approved to treat certain bacterial infections in children older than 1 year of age. (For children ages 15 years and older, dosages are the same as for adults.)
For children older than 1 year and younger than 15 years, doctors calculate cephalexin dosages based on the child’s body weight. For reference, 1 kilogram (kg) equals 2.2 pounds (lb). Recommended dosages for this age group are described in the table below:
| Condition | Recommended dosages, which are usually given for 7 to 14 days |
|---|---|
| ear infection | 75 mg to 100 mg per kg of body weight per day, given in divided doses, every 6 hours |
| respiratory tract, skin, UTI, and bone infections | 25 mg to 50 mg per kg of body weight per day, given in divided doses, usually every 6 or 12 hours |
| severe infections | 50 mg to 100 mg per kg of body weight per day, given in divided doses, usually every 6 or 12 hours |
For example, a child weighing 30 kg (about 66 lb) with a respiratory tract infection may be prescribed a daily dosage of 750 mg to 1,500 mg. This would be calculated as 25 mg to 50 mg of the drug per kg of body weight. It would be given in divided doses throughout the day as instructed by a doctor.
Dosage adjustments for cephalexin
Your doctor will prescribe a dosage of cephalexin oral forms based on several factors, including:
- the specific condition being treated and how severe it is
- your age
- other health conditions you may have
Specifically, if you have kidney problems, your doctor may reduce your cephalexin dosage in oral forms. If your kidneys are not working well, talk with your doctor before starting cephalexin treatment.
How cephalexin is taken
Cephalexin oral forms are swallowed, with or without food. You’ll likely take the medication one to four times a day, depending on your dosage.
Your doctor may advise that you take cephalexin around the same time each day. This can help the drug work more effectively because it keeps a consistent amount of the drug in your body and helps you stick to a routine.
If it’s hard for you to swallow tablets, view this article for tips on how to swallow pills. It provides suggestions for swallowing medications in pill form.
Also, be sure to talk with your doctor or pharmacist if you’re having difficulty taking your medication. They can offer recommendations on how to take it.
Missed dose of cephalexin
It’s important that you don’t miss a dose or stop taking cephalexin before you finish your treatment course. If you do so, your infection may get worse or not improve.
Talk with your doctor or pharmacist right away if you realize you forgot a dose of cephalexin. They may advise you to take the missed dose. Or they may advise you to skip it and take your next dose as scheduled.
To help you remember to take your cephalexin doses, see this article on medication reminder tips. You could also try:
- downloading a reminder app on your phone
- setting an alarm
- putting a note where you’ll see it, such as on your calendar, bathroom mirror, or bedside table
Frequently asked questions
Below are answers to some commonly asked questions about cephalexin oral forms and dosage.
Is there a recommended dosage of 500 mg four times per day for cephalexin?
Yes, it’s possible that a doctor may prescribe a dosage of 500 mg four times per day. To view usual cephalexin dosages, see the “Dosage of cephalexin” section on this page.
For severe infections, doctors may prescribe cephalexin at up to 4 g per day, divided into two or four doses. For some tooth infections, dentists may prescribe 500 mg four times per day.
Talk with your doctor about the cephalexin dosage that’s right for you.
What is the cephalexin dosage for a UTI in adults?
For a UTI in adults, the typical dose of cephalexin is 250 mg taken every 6 hours. Or your doctor may prescribe a dose of 500 mg every 12 hours. You will need to take cephalexin for 7 to 14 days. Your doctor will let you know the dosage and treatment duration that’s right for you.
If you have a severe UTI infection, your doctor may prescribe up to 4 g per day, divided into two or four equal doses.
In some older adults (ages 65 years and older), the kidneys may process cephalexin more slowly. This means more of the drug can stay in the body for a longer time, which may increase the risk of side effects. For this reason, doctors may adjust the dosing schedule of cephalexin for older adults.
Can cephalexin be prescribed for a tooth infection? If so, what’s the dosage?
Yes, dentists may prescribe cephalexin for tooth infections, such as abscesses and gum infections.
The American Dental Association recommends a cephalexin oral dose of 500 mg four times daily in adults with a mild allergy to penicillin (as an alternative to penicillin-related drugs). This dose will likely be taken for 3 to 7 days to treat a tooth infection. But be sure to take the dosage your dentist or doctor prescribes.
If you’d like, ask your dentist for more information about medications used for tooth infections. Your dentist can recommend a treatment option that’s right for you.
Is cephalexin taken long term?
No, doctors don’t usually prescribe cephalexin as a long-term treatment. It’s usually recommended as a short-term treatment.
Most people will likely take cephalexin oral forms for 7 to 14 days, depending on the condition being treated. If you and your doctor determine that it’s safe and effective for your condition, you’ll likely take cephalexin for the short term.
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Get free cardOverdose of cephalexin
It’s important that you do not take more cephalexin oral forms than your doctor prescribes. Doing so can lead to harmful effects.
Symptoms of cephalexin overdose
Symptoms of an overdose can include:
- nausea
- vomiting
- abdominal pain
- diarrhea
- blood in your urine
What to do if you take too much cephalexin
If you think you’ve taken too much cephalexin, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have severe symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.
Summary
The drugmaker provides recommended dosages of cephalexin, which is used in adults and some children to treat bacterial infections.
However, your doctor will determine the dosage that’s right for you. If you have any questions or concerns about the dosage of cephalexin, speak with a doctor or pharmacist.
Disclaimer: While Optum Perks strives for factual, comprehensive, and current information, this article is not a substitute for a licensed healthcare professional’s expertise. Always consult a doctor before taking or discontinuing any medication. Drug information is subject to change and may not cover all uses, directions, precautions, warnings, interactions, reactions, or adverse effects. The lack of a warning does not guarantee a drug’s safety, effectiveness, or appropriateness for all patients or specific uses.