Cephalexin: What You Need to Know Fast
Cephalexin is a common oral antibiotic that treats many everyday infections. It’s been around for decades and still works well for skin infections, UTIs, and some throat and ear infections. If your doctor mentions cephalexin, this page helps you understand when it’s useful, how to take it safely, and what to watch for.
Dosage & how to take
Adults often take 250–500 mg every 6–12 hours depending on the infection. For simple skin or throat infections, 500 mg twice daily is common. Children’s doses are based on weight—doctors usually write that out as mg per kg. Take it with or without food; swallowing with food can reduce stomach upset. Finish the full course even if you feel better after a couple of days—stopping early can let the infection come back stronger.
If you miss a dose, take it as soon as you remember unless it’s almost time for the next dose. Don’t double up to catch up. People with kidney problems often need lower doses or longer spacing—tell your prescriber about any kidney disease.
Side effects & warnings
Most people tolerate cephalexin well. The most common side effects are diarrhea, nausea, and mild stomach pain. If you see severe diarrhea, especially with blood or fever, contact a doctor—this can be a sign of C. difficile infection. Allergic reactions range from rash and itching to rare but serious swelling or trouble breathing. If you’re allergic to penicillin, mention it; many people with penicillin allergy can still react to cephalosporins like cephalexin, so your doctor may choose a different drug.
Other cautions: probenecid can raise cephalexin levels, so tell your provider about gout medicines. Pregnant or breastfeeding? Cephalexin is commonly used in pregnancy but always check with your clinician. Watch for changes in kidney function—older adults may need dose changes.
When to call a doctor: fever that doesn’t improve, spreading redness or swelling at a wound, persistent vomiting, jaundice (yellow skin/eyes), or any signs of a severe allergic reaction. Don’t try to treat serious infections without medical advice.
Buying and safety tips: cephalexin requires a prescription in most countries. Avoid sketchy online pharmacies that sell antibiotics without a prescription—fake or substandard pills are common and risky. Look for verified pharmacy seals, clear contact info, and a licensed pharmacist. If ordering online, keep a copy of the prescription and check the pill appearance against trusted photos or pharmacy info.
Storage is simple: keep tablets in their original container at room temperature, away from moisture. Dispose of leftover antibiotics—don’t save them for next time or share with others.
Want a quick checklist? 1) Confirm the diagnosis with a clinician. 2) Use the right dose and finish the course. 3) Watch for allergy signs and severe diarrhea. 4) Buy only from trusted pharmacies with prescriptions. That keeps treatment safe and effective.
