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EspañolCephalexin overview
BRAND NAMES:
Keflex (discontinued)
Generic Names:
Cephalexin
Uses:
Treats bacterial infections
Therapeutic Classes:
Antibiotic, cephalosporin
Forms:
Capsule, tablet, oral suspension (liquid)
How it’s taken:
By mouth
What is Cephalexin used for?
Cephalexin is a cephalosporin antibiotic used to treat bacterial infections including acne, respiratory tract infections, ear infections, bone infections, skin infections, and urinary tract infections.
What form(s) does Cephalexin come in
Capsule
250 mg
333 mg
500 mg
750 mg
Tablet
250 mg
500 mg
Oral suspension (liquid)
125 mg/5 mL
250 mg/5 mL
What are common Cephalexin doses?
Bacterial infections: 1000–4000 mg per day divided into four doses every 6 hours or two doses every 12 hours for 7–14 days
Strep throat: 500 mg by mouth every 12 hours for ten days
Uncomplicated urinary tract infection: 500 mg by mouth every 12 hours for 3–7 days or 250–500 mg by mouth every 6 hours for 3–7 days
Bacterial skin or skin structure infection: 250 mg every 6 hours or 500 mg every 12 hours
Middle ear infections in children and teens: 75–100 mg/kg per day taken in three or four divided doses
Children, seniors, and people with kidney disease may require lower doses. Find out more about cephalexin dosages, forms, and strengths here.
Common Cephalexin prescriptions
Cephalexin
100ml of 125mg/5ml bottleCephalexin
100ml of 250mg/5ml bottleCephalexin
200ml of 125mg/5ml bottleCephalexin
200ml of 250mg/5ml bottleCephalexin
250mg capsuleCephalexin
500mg capsuleCephalexin
750mg capsuleCephalexin
250mg tabletCephalexin
500mg tablet
How to take Cephalexin
Your doctor will tell you how much medicine to use. Do not use more than directed.
You may take your medicine with food or milk to avoid stomach upset.
Take all of the medicine in your prescription to clear up your infection, even if you feel better after the first few doses.
Swallow the capsule or tablet whole.
Store cephalexin tablets or capsules at room temperature.
Shake the oral suspension before measuring a dose.
Measure the dose using a calibrated oral syringe or medicine cup. Do not use kitchen or table utensils.
Store the oral suspension in a closed bottle in the refrigerator. Do not freeze.
The oral suspension can be stored for 14 days. After 14 days, throw away the bottle and any unused medicine.
What to do if you miss a dose of Cephalexin
Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose.
Do not take extra medicine to make up for a missed dose.
Cephalexin contraindications
Do not use this medicine if you have had an allergic reaction to cephalexin or another cephalosporin medicine.
Cephalexin warnings
Tell any doctor or other healthcare provider who treats you that you are using this medicine.
Your doctor may need regular visits and lab tests to check on the effects of this medicine. Keep all appointments.
This medicine can cause severe diarrhea due to bacterial imbalance in the gut. It can occur up to 2 months after you stop taking cephalexin. Call your healthcare provider if the diarrhea becomes severe, does not stop, or is bloody. Do not take any medicine to stop diarrhea until you have talked to your doctor.
Like many antibiotics, cephalexin can cause serious allergic reactions. Immediately stop taking the medicine at any sign of an allergic reaction. Get emergency medical help if you have signs of a severe allergic reaction such as swelling or trouble breathing.
Cephalexin can bring on seizures. Stop the medicine immediately if you experience a seizure and immediately talk to a healthcare provider.
Before taking this medicine, tell your doctor if you are pregnant or breastfeeding.
Also, tell your healthcare provider if you have:
Drug allergies
Kidney disease
Liver disease
A history of intestinal problems, particularly colitis
Cephalexin interactions
To avoid potentially hazardous drug interactions, tell the prescribing healthcare provider about all prescription drugs, over-the-counter medicines, and supplements you are using before taking cephalexin.
Tell other healthcare providers you are using this medicine before they prescribe new medications.
Before taking cephalexin, tell your doctor if you are currently using the diabetes drug metformin or the gout treatment probenecid.
Find out more about cephalexin interactions to avoid here.
Cephalexin side effects
Serious side effects
Talk to a doctor if you notice any signs or symptoms of possible serious side effects, including:
Severe diarrhea, especially if bloody or ongoing
Severe stomach pain, vomiting
Seizures
Blistering, peeling, red skin rash
Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
Less serious side effects
Mild diarrhea
Nausea
Vomiting
Find more detailed information about cephalexin side effects here.