Biaxin (clarithromycin): what it treats and what to watch for

Need a quick, useful run‑through of Biaxin? This is clarithromycin, a macrolide antibiotic doctors prescribe for sinusitis, bronchitis, skin infections, and as part of some H. pylori treatments. It kills bacteria by stopping them from making proteins. Read on for plain‑English advice on dose, side effects, drug interactions, and smart safety tips.

Typical doses and how to take it

Adults usually take 250–500 mg twice a day. Courses commonly last 7–14 days depending on the infection. For H. pylori, clarithromycin is often used at 500 mg twice daily in a combination therapy with another antibiotic and a proton pump inhibitor. Take Biaxin with or without food—food can reduce stomach upset for some people. Always finish the full course even if you feel better; stopping early can let bacteria survive and become resistant.

Common side effects and red flags

Expect the usual antibiotic complaints: stomach pain, nausea, diarrhea, and a metallic or bitter taste. Headache and mild rash happen too. Serious but uncommon problems include liver enzyme changes, severe allergic reactions, and heart rhythm changes (QT prolongation). If you get severe diarrhea, yellowing of the skin/eyes, fast irregular heartbeat, chest pain, or swelling of face/throat, stop the drug and get medical help.

Clarithromycin can also trigger Clostridioides difficile (C. diff) colitis — if you have very bad, persistent diarrhea or fever, contact your provider right away.

Pregnancy and breastfeeding: doctors usually avoid clarithromycin in pregnancy unless clearly needed. If you’re breastfeeding, mention it so the prescriber can weigh risks and watch the baby for unusual symptoms.

Kidney or liver disease: dose changes may be needed for severe kidney or liver problems. Tell your doctor about any chronic conditions before you start Biaxin.

Drug interactions to watch for

Clarithromycin blocks an enzyme (CYP3A4) that helps clear many drugs. That can raise levels of some medicines and cause trouble. Don’t take simvastatin or lovastatin with clarithromycin — that combo can lead to dangerous muscle breakdown. Other important interactions are with warfarin (bleeding risk), colchicine, certain antiarrhythmics, and some benzodiazepines. Always give your pharmacist a full list of prescriptions, over‑the‑counter drugs, and supplements before starting Biaxin.

How Biaxin compares to other macrolides

Compared with azithromycin (Zithromax), clarithromycin has more drug interactions and sometimes more stomach upset, but it’s often preferred in H. pylori therapy and some respiratory infections. Your doctor chooses based on the infection, your other meds, and past antibiotic response.

Practical tips: store tablets at room temperature, keep out of reach of kids, and don’t share antibiotics with anyone else. If you have questions about side effects or interactions, call your pharmacist or prescriber—better to check than risk a preventable problem.