cephalexin
Cephalexin, also commonly known as Keflex, is a cephalosporin antibiotic for people ages 1 year and older. It can treat many types of bacterial infections. This includes ear infections, skin infections like cellulitis, urinary tract infections (UTIs), and strep throat. Cephalexin comes as capsules, tablets, and a liquid suspension. It's taken by mouth 2 to 4 times per day. Side effects can include nausea, vomiting, and diarrhea. Cephalexin is a generic medication; its brand name Keflex is no longer available.
What is Cephalexin?
What is Cephalexin used for?
- Respiratory tract infections (e.g., strep throat)
- Ear infections
- Skin infections (e.g., cellulitis)
- Bone infections
- Urinary tract infections (UTIs)
- Reproductive system infections (e.g., prostatitis)
How Cephalexin works
Cephalexin is a type of cephalosporin antibiotic. It works by stopping bacteria from making a protective covering around themselves. This kills the bacteria and helps treat the infection.
Drug facts
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Side effects of Cephalexin
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
- Diarrhea
- Nausea
- Vomiting
- Indigestion
- Stomach pain
Less Common Side Effects
- Dizziness
- Fatigue
- Headache
- Confusion
- Joint pain
- Yeast infection
Cephalexin serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Allergic reactions: hives; rash; blisters; peeling skin; swelling of the lips, tongue, or face; trouble breathing
- Infectious diarrhea (C. difficile-related diarrhea): fever, nausea, foul-smelling diarrhea, frequent bowel movements (up to 15 times per day)
More on Cephalexin side effects
The following Cephalexin side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- Redness, blistering, peeling, or loosening of the skin, including inside the mouth
- Severe diarrhea, fever
- Unusual vaginal discharge, itching, or odor
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
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Pros and cons of Cephalexin
Pros
- Treats several common types of bacterial infections
- Okay for children as young as 1 year old to take
- Available as a liquid for people who have trouble swallowing pills
Cons
- Usually need to take a few times per day
- Might not be able to take if you're allergic to penicillins or other cephalosporin antibiotics
- Not recommended for the cold or flu (these are viral illnesses, not bacterial infections)
Pharmacist tips for Cephalexin
- Take cephalexin exactly the way your prescriber tells you. Keep taking it until you finish the full course of treatment, even if you feel better. Stopping too early can make your infection come back and be harder to treat.
- You can take cephalexin with or without food. If it makes your stomach upset, you can try taking it with food next time to see if that helps. Avoid spicy or acidic foods, though, because these can make stomach upset more likely.
- Swallow the cephalexin tablet or capsule whole. Don't crush or chew it because this could damage the medication. If you have trouble swallowing pills whole, ask your prescriber to switch you to the cephalexin liquid suspension.
- Cephalexin can cause mild diarrhea that usually goes away after you stop taking it. But watch for more severe or unusual diarrhea. Get medical help right away if you have watery or bloody diarrhea, diarrhea many times a day, fever, or stomach cramps during or after treatment. These can be signs of serious infectious diarrhea that needs to be treated quickly.
- Get medical help as soon as possible if you have a rash, itchy or peeling skin, trouble breathing, or swelling in your face or mouth. These could be signs of a severe allergic reaction to cephalexin.
- It's best to avoid drinking alcohol while taking cephalexin. Alcohol can make side effects like nausea and vomiting worse. Drinking alcohol while sick might make it harder for you to get better too. Talk to your prescriber or care team about your drinking habits and how to take this antibiotic safely.
- Let your prescriber or the urgent care team know that you're pregnant. Cephalexin is generally considered safe to take while pregnant. But it's always a good idea to discuss the risks and benefits of taking the antibiotic with your care team first.
- Tell your prescriber or the urgent care team if you're breastfeeding. Cephalexin is usually a safe antibiotic to take while breastfeeding. Small amounts can pass into breast milk, but it doesn't seem to cause serious harm to babies. Talk to your care team if you have concerns about breastfeeding while taking cephalexin.
For the cephalexin liquid suspension:
- The pharmacist will prepare the cephalexin liquid when you pick it up from the pharmacy. They'll also give you medication dose cups or oral syringes to use to measure out the dose.
- Shake the cephalexin liquid bottle well before measuring out the dose. This makes sure the medication is mixed evenly before you take it.
- Use a dosing cup or oral syringe to measure out the cephalexin liquid. Don't use kitchen spoons because they aren't accurate and using them might cause you to take the wrong dose.
- Store the cephalexin liquid suspension in the refrigerator for up to 14 days. After 14 days, throw away the bottle, even if there's still some medication left.
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Risks and warnings for Cephalexin
Cephalexin can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Allergic reactions
- Risk factors: Allergy to penicillin or other cephalosporin antibiotics
Some people can have allergic reactions to cephalexin. Mild reactions can include a rash or hives. More serious, life-threatening reactions can include blisters, peeling skin, swelling of the face, and anaphylaxis.
Tell your healthcare team if you're allergic to any antibiotics, especially penicillins or other cephalosporins. They can make sure cephalexin is safe for you.
Get medical help right away if you have a rash, hives, red or peeling skin, swelling of the lips or tongue, or trouble breathing after taking cephalexin. These can be signs of an allergic reaction.
Diarrhea from Clostridioides difficile infection
Antibiotics including cephalexin can change the normal bacteria in your gut. This can let harmful bacteria called Clostridioides difficile (C. diff) grow too much and cause a serious infection. This infection can lead to severe diarrhea, even up to 2 months after you stop the antibiotic.
It's important to know the difference between mild diarrhea from cephalexin and serious diarrhea from C. diff. Signs of a C. diff infection include fever, nausea, foul-smelling diarrhea, and frequent bowel movements. Get medical help right away if you have any signs of this infectious diarrhea. This can be a medical emergency and should get treated as soon as possible.
Seizures
- Risk factors: Kidney problems | Taking high doses of cephalexin
Cephalexin might raise your risk of seizures, especially when the dose is too high. You also might be at risk if you have kidney problems and the cephalexin dose isn't lowered enough for you. When the kidneys don't work well, the medication can build up in the body and raise the risk of side effects, including seizures.
Tell your prescriber or the urgent care team if you've had seizures or if you have kidney problems. They can make sure that cephalexin is safe for you. If you have a seizure while taking this medication, get medical help right away.
Higher risk of bleeding
- Risk factors: Kidney problems | Liver problems | Poor nutrition | Taking blood-thinning medications
Cephalexin might raise your risk of bleeding. The risk might be higher if you have kidney problems, liver problems, or poor nutrition. It's also higher if you take an anticoagulant (blood thinner).
Talk to your prescriber or the urgent care team about your bleeding risk before taking cephalexin. If you take a blood thinner, the prescriber might ask you to follow up with the specialist who manages that medication for you. Watch for signs of bleeding, like easy bleeding or bruising or blood in your urine or stool. If this happens, tell your prescriber.
Possible development of drug-resistant bacteria
Take cephalexin exactly as your prescriber told you. Don't take it for a shorter or longer time, and don't take it for other illnesses. Otherwise, it can raise your risk of developing infections caused by drug-resistant bacteria. These infections can be very serious and harder to treat.
Cephalexin dosage
Bottle of oral suspension| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 200ml of 125mg/5ml | 1 bottle | $13.11 | $13.11 |
| 100ml of 125mg/5ml | 1 bottle | $11.08 | $11.08 |
| 200ml of 250mg/5ml | 1 bottle | $18.98 | $18.98 |
| 100ml of 250mg/5ml | 1 bottle | $12.97 | $12.97 |
Typical dosage for Cephalexin
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Ages 15 years and older: The typical dose is 250 mg by mouth every 6 hours. Another option is 500 mg by mouth every 12 hours. For more severe infections, you might need a higher dose (up to a total of 4 grams per day, split into 2 to 4 doses). Treatment often lasts for 7 to 14 days.
-
Ages 1 to under 15 years: The dose is based on your child's body weight. The typical total daily dose is 25 mg/kg to 50 mg/kg of body weight by mouth. This total dose is split up into smaller doses throughout the day, as directed by the prescriber. For more severe infections, such as an ear infection, your child might need a higher dose of up to 100 mg/kg per day. Treatment often lasts for 7 to 14 days.
Your dose might differ if you have kidney problems.
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How much does Cephalexin cost?
$9.96
Cephalexin contraindications
Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Cephalexin will not be safe for you to take.
- Known allergy to other cephalosporin antibiotics
What are alternatives to Cephalexin?
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