cephalexin
Cephalexin is a common antibiotic that's used to treat many different bacterial infections including urinary tract infections (UTIs), ear infections, and sinus infections, to name a few. Cephalexin is a cephalosporin antibiotic that kills bacteria to fight the infection. It's safe to use in people over the age of 1, and it's typically taken by mouth 2 to 4 times per day. This medication is available as a lower-cost generic capsule, tablet, and suspension; the brand name Keflex is no longer available. Side effects can include nausea, vomiting, and diarrhea.
What is Cephalexin?
What is Cephalexin used for?
- Respiratory tract infections
- Ear infections
- Skin infections
- Bone infections
- Urinary tract infections (UTIs)
- Reproductive system infections
How Cephalexin works
Cephalexin is a cephalosporin antibiotic. It kills bacteria by preventing the bacteria from making a covering around themselves for protection.
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; swelling of the lips, tongue, or face; difficulty breathing
- Infectious (C. difficile-related) diarrhea: foul-smelling diarrhea, fever, nausea, 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 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
- Can use for adults and children over the age of 1
- Available as a liquid for people who have trouble swallowing pills
- Available as a lower-cost generic
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 as prescribed. Make sure to finish your treatment course, even if you're feeling better. Stopping the medication earlier than prescribed can make your infection come back and become harder to treat.
- You can take cephalexin with or without food. Taking the medication with food can help if it's upsetting your stomach.
- If you're taking the cephalexin tablet or capsule, don't crush or chew it. This could damage the medication. Ask your prescriber to switch you to the cephalexin oral suspension (liquid) if you're having trouble swallowing pills.
- Cephalexin can cause diarrhea, but it should go away when you stop taking it. Contact your healthcare team right away if you start to have watery or bloody diarrhea, fever, fatigue, or stomach cramps anytime during treatment or after stopping cephalexin. These might be signs of a type of infectious diarrhea, which needs to be treated right away.
- Get medical attention as soon as possible if you have a rash, itchy skin, difficulty breathing, or swelling in your face or mouth. These could be signs of a severe allergic reaction.
- Cephalexin is generally considered safe to take while pregnant. Based on available information in humans, this antibiotic doesn't appear to cause harm to unborn babies during pregnancy. Let your primary care provider or the urgent care team know that you're pregnant and discuss the risks and benefits of taking cephalexin.
- Cephalexin is considered a safe antibiotic to take while breastfeeding. Low levels of the medication can be found in breast milk, but it's not expected to harm your baby. Tell the prescriber that you're nursing and discuss the risks and benefits of using cephalexin.
For the cephalexin oral suspension (liquid)
- Shake the cephalexin oral suspension bottle well before measuring out the dose.
- Make sure to only use a medication dose cup or syringe from the pharmacy to measure out your cephalexin dose. Don't use household spoons because they aren't accurate and might cause you to take the wrong dose. Ask the pharmacy for extras.
- Store the cephalexin 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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Common questions about Cephalexin
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
Allergic reactions to cephalexin are possible, including rash, hives, or more seriously, life-threatening reactions like facial swelling and anaphylaxis (closing of the throat). Let your healthcare team know if you have an allergy to antibiotics, especially penicillin or other cephalosporin antibiotics. Get medical attention immediately if you notice rash, hives, red skin, swelling of the lips or tongue, or difficulty breathing after you take cephalexin.
Diarrhea from Clostridioides difficile infection
Antibiotics, including cephalexin, raise your risk of getting infected with a bacteria called Clostridioides difficile (C. diff). Antibiotics change the amount of normal bacteria in your stomach and intestines. This can cause C. diff to overgrow in your gut and lead to an infection. And C. diff infection can cause diarrhea that can sometimes be life-threatening.
It's important to recognize the difference between diarrhea as a side effect of cephalexin and this type of infectious diarrhea. C. diff-related diarrhea can cause rapid heart rate, foul-smelling diarrhea, fever, nausea, and frequent bowel movements (even up to 15 times per day) and is an emergency. Get medical attention right away if you experience any of these symptoms so you can get tested for C. diff infection and get appropriate treatment.
Development of drug-resistant bacteria
Take cephalexin exactly as prescribed. Using cephalexin for any shorter or longer periods of time or taking the antibiotic for other illnesses can raise your risk for developing infections caused by drug-resistant bacteria. This raises your risk for severe and life-threatening infections that might be difficult to treat.
Seizures
- Risk factors: Kidney problems | Taking high doses of cephalexin
Cephalexin might raise your risk of seizures, especially when the antibiotic is used at doses that are too high. You also might be at risk for seizures if you have kidney problems and the dose of cephalexin wasn't appropriately lowered to adjust for the fact that your kidneys can't help get rid of the medication from your body as well. Discuss with your primary care provider or the urgent care team if you've had a seizure before or if you have kidney problems to make sure cephalexin is safe for you.
Higher risk of bleeding
- Risk factors: Kidney problems | Liver problems | Poor nutrition | Taking blood-thinning medications
Cephalexin might raise your risk of bleeding. You're at a higher risk if you have kidney problems, liver problems, or poor nutrition or if you're taking an anticoagulant (blood thinner). Discuss your risk for bleeding with your primary care provider or the urgent care team, and watch out for signs of too much bleeding (e.g., unexplained bruising, blood in your urine or stool). If you're taking a blood-thinning medication, the prescriber might recommend that you follow up with the specialist who's monitoring your blood-thinning medication for blood testing or dose adjustments.
Cephalexin dosage
Bottle of oral suspension| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 200ml of 125mg/5ml | 1 bottle | $20.91 | $20.91 |
| 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
Cephalexin is available as capsules, tablets, and liquid suspensions.
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Adults and children 15 years of age or older: The typical dose is 250 mg by mouth every 6 hours. An alternative dose is 500 mg by mouth every 12 hours. You'll typically need to take cephalexin for 7 to 14 days. For more severe infections, you might need a higher dose (up to 4 grams total per day).
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Children age 1 to up to 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. Your child will typically need to take cephalexin for 7 to 14 days. For more severe infections, such as an ear infection, your child might need a higher dose of up to 100 mg/kg per day.
Your dose might differ if you have kidney problems.
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How much does Cephalexin cost?
$8.49
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.
- Severe allergy to other cephalosporin antibiotics or to beta-lactam antibiotics
What are alternatives to Cephalexin?
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