Cephalexin: What It Treats and How to Use It Safely

Cephalexin is a common antibiotic used for skin infections, urinary tract infections, ear infections, and some respiratory infections. It belongs to the cephalosporin class and kills bacteria by stopping their cell wall growth. Doctors prescribe it when the likely bacteria respond to cephalosporins. Take it exactly as your prescriber tells you.

How to take cephalexin: take the capsule or liquid with a full glass of water. You can take it with or without food, but if it upsets your stomach, take it after a meal. Finish the full course even if you feel better early; stopping may let bacteria return stronger. For adults common doses range from 250 mg to 500 mg every 6 to 12 hours depending on the infection. Kids get doses based on weight.

Side effects and warnings

Most people tolerate cephalexin well. The usual side effects are diarrhea, nausea, stomach pain, and yeast infections. If you see a rash, swelling, trouble breathing, or severe diarrhea with blood or fever, stop the drug and seek medical help. People with a severe penicillin allergy may react to cephalexin; tell your provider if you had hives, anaphylaxis, or throat tightness from penicillin.

Cephalexin can interact with other drugs. Tell your provider about blood thinners, probenecid, and metformin. If you take long courses, your provider may check kidney function or watch for unusual symptoms. Pregnant and breastfeeding people should discuss risks and benefits; cephalexin is often used in pregnancy but only when needed.

Practical tips for buying and storing

Only buy antibiotics from reputable pharmacies with a prescription. Avoid random online sources that do not require a valid prescription. Store cephalexin at room temperature away from moisture and heat. Discard unused liquid formulations after the recommended time on the label.

Got questions about dose adjustments, missed doses, or side effects? Ask your pharmacist or doctor. If your infection does not improve in 48 to 72 hours or gets worse, call your provider. For recurring infections, your provider may order tests to find the right antibiotic.

Quick checklist: confirm it treats the bug you have, follow the full course, watch for allergic reactions, avoid sharing antibiotics, and use reputable pharmacies. Cephalexin is reliable for many common infections when used correctly. If you want more details on specific uses or alternatives, search our site or ask a healthcare professional.

How long does it work and what to expect: Most people start to feel better within 48 to 72 hours. Fever and pain usually drop first, while cough or ear drainage may take longer. If symptoms linger beyond three days without improvement, your doctor may switch antibiotics or order a culture to identify the bacteria. Do not stop early because of side effects without talking to your provider.

Special groups: older adults and people with kidney problems often need lower doses. Always share a full list of medicines and health conditions before starting cephalexin so your provider can tailor treatment safely and promptly.