Clarithromycin — Compare Prices at US & Canada Pharmacies

Clarithromycin (Biaxin) is a macrolide antibiotic prescribed for a range of bacterial infections:

• Respiratory infections — bronchitis, community-acquired pneumonia, and sinusitis
• Skin and soft tissue infections
• Strep throat and certain ear infections, especially in people with a penicillin allergy
• H. pylori eradication, as part of a multi-drug regimen for stomach ulcers caused by that bacterium
• Prevention and treatment of Mycobacterium avium complex (MAC) infection in people with advanced HIV

It's not effective against viral infections like a cold or the flu, and — as with any antibiotic — it should only be used for a confirmed or strongly suspected bacterial infection.

Helicobacter pylori is a bacterium that lives in the stomach lining and causes a large share of peptic ulcers, as well as raising stomach cancer risk over time. Clearing it typically requires combination therapy — clarithromycin paired with another antibiotic (commonly amoxicillin or metronidazole) plus an acid-reducing medication, taken together for one to two weeks. No single antibiotic reliably eradicates H. pylori on its own, which is why the combination matters more than any one ingredient.

Clarithromycin's role here isn't automatic, though — resistance to macrolide antibiotics has been rising in H. pylori strains in some regions, and if you've taken a macrolide (clarithromycin, azithromycin, or erythromycin) recently for something else, that specific strain may already be less likely to respond. Your provider may choose a different combination regimen based on local resistance patterns or your treatment history, and may recommend a follow-up breath or stool test after treatment to confirm the infection actually cleared.

No — clarithromycin (Biaxin) and azithromycin (Zithromax, sold as the "Z-Pak") are different drugs in the same macrolide family, along with erythromycin. They work the same basic way and treat overlapping infections, but they're not interchangeable:

• Dosing schedule. A Z-Pak is a short, five-day, once-daily course. Clarithromycin is typically taken twice daily for 7 to 14 days (or once daily as the extended-release Biaxin XL).
• Drug interactions. Clarithromycin is a much stronger inhibitor of the liver enzyme CYP3A4, which is why it interacts with far more medications — especially statins — than azithromycin does. Azithromycin is generally the "cleaner" choice when a patient is on multiple other medications.
• Distinct uses. Clarithromycin has a specific role in H. pylori ulcer treatment that azithromycin doesn't share.

If you've been prescribed one and are wondering whether it's "the same as a Z-Pak," the honest answer is: related, but your prescriber chose the specific one for a reason — usually the interaction profile, the infection, or local resistance patterns.

Yes, more so than most antibiotics — clarithromycin strongly inhibits CYP3A4, a liver enzyme many common medications depend on to be broken down, so combining it with those drugs can let them build up to unsafe levels.

• Statins, especially simvastatin and lovastatin, are the interaction that comes up most often in practice — clarithromycin can raise statin levels enough to meaningfully increase the risk of muscle damage (rhabdomyolysis). Many prescribers pause the statin or switch to one with less CYP3A4 dependence (like pravastatin or rosuvastatin) during a course of clarithromycin.
• Colchicine (for gout) is a serious, potentially life-threatening interaction, particularly in anyone with reduced kidney or liver function — this combination needs specific caution and sometimes avoidance altogether.
• Warfarin — clarithromycin can meaningfully strengthen its blood-thinning effect, raising bleeding risk; closer monitoring is typically needed.
• Other QT-prolonging medications (certain antiarrhythmics, some antipsychotics and antidepressants, and other macrolides) — combining them raises the risk of a dangerous heart rhythm disturbance.

This isn't a complete list — clarithromycin's CYP3A4 effect touches many other drug classes too, from certain blood pressure medications to some seizure medications. Give your prescriber and pharmacist your full medication list, including over-the-counter drugs and supplements, before starting it.

Worth flagging specifically: in 2018, the FDA issued a drug safety communication after a long-term follow-up study of people with coronary artery disease found a small but statistically significant increase in deaths, years later, among those who'd taken a short course of clarithromycin compared with placebo. The reason for this isn't fully understood, and the increased risk hasn't been clearly demonstrated in people without heart disease.

As a result, the FDA recommends that prescribers weigh the risks and benefits carefully — and consider an alternative antibiotic where a reasonable one exists — for patients with known coronary artery disease. If you have heart disease and clarithromycin is being considered for you, it's a reasonable question to raise with your provider, not a reason to assume it's off the table entirely.

There's no FDA-documented severe interaction between clarithromycin and alcohol — it's not in the same category as metronidazole or similar drugs that can cause a genuinely dangerous reaction. That said, alcohol can worsen the nausea and stomach upset clarithromycin commonly causes, and heavy drinking is best avoided with any medication that's processed by the liver, given clarithromycin's own (uncommon but real) liver-related side effects. Keeping it light or skipping alcohol until you finish your course is the more conservative approach.

Take clarithromycin exactly as prescribed, with or without food — food can help if it upsets your stomach. Swallow extended-release (Biaxin XL) tablets whole; don't crush or chew them. If you miss a dose, take it as soon as you remember unless your next dose is almost due, in which case skip the missed one rather than doubling up. Finish the entire course even after you start feeling better — stopping early lets surviving bacteria regrow and contributes to antibiotic resistance.

Give your provider your complete medication list before starting, given how many drugs clarithromycin can interact with, and mention any history of heart rhythm problems, liver disease, or coronary artery disease. Report a persistent or severe metallic taste, unusual fatigue, dark urine, or yellowing skin or eyes — these are worth a call to your provider rather than waiting them out.