Cephalexin is a generic drug prescribed for bacterial infections. It belongs to the cephalosporin antibiotic drug class.
- Cephalexin oral capsule is a generic drug. No brand-name versions are currently available. (A brand-name version called Keflex used to be available but has been discontinued.)
- Cephalexin also comes as a tablet and a liquid suspension that you take by mouth.
- Cephalexin oral capsule is used to treat certain infections caused by bacteria.
- Allergy to beta-lactam medications warning: If you’re allergic to beta-lactam medications, many of which are antibiotics, you should not take this drug. You could have a serious allergic reaction.
- Antibiotic-associated diarrhea warning: Almost all antibiotics, including cephalexin, can cause a reaction that leads to diarrhea. In addition to diarrhea, this reaction can cause severe inflammation of your colon. Severe cases of this reaction can be fatal (cause death). Call your doctor if you have diarrhea while taking or after taking this drug.
Cephalexin oral capsule is a generic prescription drug. Generic drugs usually cost less than the brand-name version. Sometimes, they may not be available in all strengths or forms as the brand-name drug.
Cephalexin also comes as an oral tablet and an oral suspension.
Cephalexin uses
Cephalexin is used to treat certain infections caused by bacteria. These infections include:
- respiratory tract infections
- otitis media (middle ear infections)
- skin and skin structure infections
- bone infections
- genitourinary (urinary tract) infections
Cephalexin can be used in adults and children 1 year and older.
How it works
Cephalexin belongs to a class of drugs called cephalosporins (antibiotics). A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.
Cephalexin works by interfering with the formation of the bacteria’s cell walls. This ruptures the walls and kills the bacteria.
Doctors only prescribe cepalexin to treat bacterial infections. They don’t prescribe it to treat viruses such as the common cold.
Cephalexin oral capsule doesn’t cause drowsiness. However, it can cause other side effects.
More common side effects
The more common side effects of cephalexin oral capsule include:
- diarrhea (the most common side effect in clinical trials)
- indigestion
- irritation or inflammation of your stomach lining
- abdominal pain
If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk with your doctor or pharmacist.
Serious side effects
Call your doctor right away if you have serious side effects. Call 911 or your local emergency number if your symptoms feel life threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:
- Allergic reaction. Symptoms can include:
- hives
- trouble breathing
- swelling of your face, lips, tongue, or throat
This dosage information is for cephalexin oral capsule. This article may not include all possible dosages and drug forms. Your dosage, drug form, and how often you take the drug will depend on:
- your age
- the condition being treated and how severe it is
- other medical conditions you have
- how you react to the first dose
Form and strengths (250 mg, 500 mg, 750 mg)
Generic: Cephalexin
- Form: Oral capsule
- Strengths: 250 milligrams (mg), 500 mg, 750 mg
Dosage for respiratory tract infection
Adult dosage (ages 18 to 64 years)
The usual dose 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.
Child dosage (ages 15 to 17 years)
The usual dose is 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.
Child dosage (ages 1 to 14 years)
25–50 mg/kg of body weight per day, taken in divided doses. Your child’s doctor may double the dose for severe infections.
This medication hasn’t been studied in children younger than 1 year for this condition.
Dosage for otitis media (middle ear infection)
Adult dosage (ages 18 to 64 years)
The usual dose 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.
Child dosage (ages 15 to 17 years)
The usual dose is 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.
Child dosage (ages 1 to 14 years)
75–100 mg/kg of body weight per day given in equally divided doses every 6 hours.
This medication hasn’t been studied in children younger than 1 year for this condition.
Dosage for skin and skin structure infection
Adult dosage (ages 18 to 64 years)
The usual dose 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.
Child dosage (ages 15 to 17 years)
The usual dose is 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.
Child dosage (ages 1 to 14 years)
25–50 mg/kg of body weight per day taken in divided doses. Your doctor may double your dose for severe infections.
This medication hasn’t been studied in children younger than 1 year for this condition.
Dosage for bone infections
Adult dosage (ages 18 to 64 years)
The usual dose 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.
Child dosage (ages 15 to 17 years)
The usual dose is 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.
Child dosage (ages 1 to 14 years)
25–50 mg/kg of body weight per day taken in divided doses. Your doctor may double your dose for severe infections.
This medication hasn’t been studied in children younger than 1 year for this condition.
Dosage for genitourinary (urinary tract) infection
Adult dosage (ages 18 to 64 years)
The usual dose 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.
Child dosage (ages 15 to 17 years)
The usual dose is 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.
Child dosage (ages 1 to 14 years)
25–50 mg/kg of body weight per day taken in divided doses. Your doctor may double your dose for severe infections.
This medication hasn’t been studied in children younger than 1 year for this condition.
Special dosage considerations
For older adults (65 years and older): The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects. Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.
For adults and children (15 years of age and older) with kidney problems:
- People with a creatinine clearance (CrCL) of 30–59 mL/min: maximum daily dose should not exceed 1 g
- People with a CrCL of 15 to 29 mL/min: 250 mg taken every 8 or 12 hours
- People with a CrCL of 5 to 14 mL/min: 250 mg every 24 hours
- People with a CrCL of 1 to 4 mL/min: 250 mg every 48 or 60 hours
Cephalexin can interact with several other medications. It can also interact with certain supplements and foods.
Before taking cephalexin, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.
Examples of drugs that can cause interactions with cephalexin are listed below.
Interactions that increase your risk of side effects
Side effects from cephalexin: Taking cephalexin with certain medications raises your risk of side effects from cephalexin. This is because the amount of cephalexin in your body is increased. An example of these drugs is probenecid.
Side effects from other drugs: Taking cephalexin with certain medications raises your risk of side effects from these drugs. An example of these drugs is metformin. Taking metformin and cephalexin together may cause kidney problems. Your doctor may adjust your dose of metformin to reduce this risk.
This drug comes with several warnings.
Allergy warning
Cephalexin can cause an allergic reaction, which can be severe. Symptoms can include:
- hives
- trouble breathing
- swelling of your face, lips, tongue, or throat
If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 911 (or your local emergency number) or go to the nearest emergency room.
Your doctor won’t prescribe cephalexin again if you’ve ever had an allergic reaction to it. Rarely, taking it again could be fatal (cause death).
Warnings for certain groups
For people with kidney problems: If you have kidney problems or a history of kidney disease, you may not be able to clear this drug from your body as effectively as usual. This may increase the levels of this drug in your body and cause more side effects. Your doctor may adjust your dose if you have kidney disease. Talk with your doctor about whether this drug is safe for you.
For pregnant people: Studies of the drug in pregnant animals have not shown a risk to the fetus. However, there aren’t enough studies on pregnant people to show the drug poses a risk to a human fetus. If you’re pregnant or planning to become pregnant, talk with your doctor about whether cephalexin is safe for you to take.
For people who are breastfeeding: Cephalexin passes into breast milk and may cause side effects in a child who is breastfed. Talk with your doctor if you’re breastfeeding. Together you can determine whether it’s worth it for you to stop breastfeeding and take cephalexin or whether you should take a different antibiotic instead.
For older adults: The kidneys of older adults (generally, 65 years and older) may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of the drug stays in your body longer. This raises your risk of side effects.
For children: This drug hasn’t been studied in children younger than 1 year of age with respiratory tract, middle ear, skin and skin structure, bone, or urinary tract infections.
Cephalexin oral capsule is a short-term drug treatment. It comes with risks if you don’t take it as prescribed.
If you stop taking the drug or don’t take it at all: If you don’t finish your course of treatment with this drug, your infection may not improve and may potentially worsen.
If you miss doses or don’t take the drug on schedule: Cephalexin may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.
If you take too much: You could have dangerous levels of this drug in your body. Symptoms may include:
- nausea
- vomiting
- stomach aches
- diarrhea
- blood in your urine
If you think you’ve taken too much of this drug, call your doctor. You can also call America’s Poison Centers at 800-222-1222 or use its online tool. However, if your symptoms are severe, call 911 or your local emergency number, or go to the nearest emergency room right away.
What to do if you miss a dose: Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Do not try to catch up by taking two doses at once. This could result in dangerous side effects.
How to tell if the drug is working: Your symptoms should be reduced by the time you complete your treatment.
As with all medications, the cost of cephalexin can vary. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.
Drug coupons: You can visit Optum Perks for price estimates of cephalexin. These estimates are based on the use of Optum Perks coupons. Note: Optum Perks coupons cannot be used with any insurance copays or benefits.
Financial and insurance assistance: If you need financial support to pay for cephalexin or need help understanding your insurance coverage, help is available. Your doctor or pharmacist may be able to recommend resources.
To learn more about saving money on prescriptions, check out this article.
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Keep the following considerations in mind if your doctor prescribes cephalexin oral capsule for you.
General
You can take cephalexin with or without food.
Storage
- Store the capsules between 59°F and 86°F (15°C and 30°C).
- Don’t store this medication in moist or damp areas, such as bathrooms.
Refills
Usually, a prescription for this medication is refillable. You should not need a new prescription to refill this medication. Your doctor will write the number of authorized refills on your prescription.
Travel
When traveling with your medication:
- Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
- Don’t worry about airport X-ray machines. They can’t hurt your medication.
- You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
- Do not put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.
Clinical monitoring
Your doctor may do blood tests to check how well your kidneys are working. If your kidneys aren’t working well, your doctor may lower your dose of this drug.
There are other drugs available to treat your condition. Some may be better suited for you than others. Talk with your doctor about other drug options that may work for you.
Disclaimer: Medical News Today 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.
