Cephalexin: what it treats and how to use it safely

Cephalexin is a common antibiotic doctors prescribe for skin infections, ear infections, throat infections, some urinary tract infections, and other bacterial problems. It works fast for many common infections, but using the right dose and the right length of time matters. Get the facts so you get better without creating resistance or avoidable side effects.

How to use cephalexin

Adults often take 250–500 mg every 6 to 12 hours depending on the infection. For children dosing is usually based on weight—common ranges are 25–50 mg per kg per day divided into doses. Your doctor will tell you the best dose and how long to take it. Take cephalexin with or without food; if it upsets your stomach, take it with a meal.

Finish the full course unless your doctor says otherwise. Stopping early can let bacteria survive and come back stronger. If you miss one dose, take it when you remember unless it’s almost time for the next one—don’t double up. People with kidney problems may need lower doses, so mention kidney disease when you get a prescription.

Side effects, allergies, and safety tips

Common side effects include nausea, diarrhea, and mild stomach pain. Most people tolerate cephalexin well, but serious reactions can happen. If you develop a rash, difficulty breathing, swelling of the face or throat, or fast heartbeat, get emergency help—these are signs of a severe allergic reaction. Also watch for severe, persistent diarrhea; that could be Clostridioides difficile and needs prompt care.

Tell your doctor if you’re allergic to penicillin or other antibiotics—cross-reactivity can occur. Cephalexin can interact with certain medicines like warfarin, making bleeding more likely, so list all your medications. Pregnant or breastfeeding? Tell your clinician; cephalexin is commonly used in pregnancy but should still be guided by a doctor.

Storage is simple: keep the tablets or liquid at room temperature away from heat and moisture. If you have the liquid form, follow the label for refrigeration and discard leftovers after the recommended time. Keep all medicines out of reach of children.

Want to buy cephalexin online? Use only licensed pharmacies that require a valid prescription. Avoid sites that offer antibiotics without asking for a prescription or that advertise extremely cheap, no-prescription drugs. Check for clear contact info, a pharmacy license number, and reviews from real customers. If you’re ever unsure, ask your local pharmacist or doctor for a safe source.

Don’t share antibiotics or use them for colds or flu—those are viral and won’t improve with cephalexin. Proper use helps you recover faster and reduces the chance of antibiotic resistance.

Call your doctor if symptoms don’t improve in 48–72 hours, if fever gets worse, or if you notice signs of an allergic reaction or severe diarrhea. Getting prompt advice can prevent complications and get you on the right treatment sooner.