Clarithromycin 250 mg

Description

Clarithromycin 250 mg Tablets: What They Treat and Which Medicines Don’t Mix With Them

Clarithromycin is a macrolide antibiotic, in the same family as azithromycin and erythromycin. It is prescribed for chest, throat, skin and stomach infections, and it is often chosen when penicillin is unsuitable. What makes it different from most antibiotics is how many other medicines it can interfere with. For that reason, this guide starts with interactions before moving on to uses, dosing patterns and side effects.

The information below is general education. It does not replace the advice of the clinician who prescribed your medicine or your pharmacist.

Clarithromycin 250 mg Snapshot

Medicine	Clarithromycin (macrolide antibiotic)
Strength	250 mg per tablet
Typical pattern	Usually twice a day; the exact dose and days are set by your prescriber
Treats	Susceptible bacterial infections only
With food?	Can be taken with or without food
Biggest safety point	Interacts with many common medicines
Prescription required	Yes

Check Your Medicines First

Clarithromycin blocks an enzyme in the liver (CYP3A4) that breaks down many other drugs. When that enzyme is slowed down, the other medicine can build up in the body and cause side effects it would not normally cause. Your prescriber and pharmacist should always see your full list, including supplements and herbal products.

Medicine type	Examples	Why it matters
Cholesterol medicines (statins)	Simvastatin, lovastatin, atorvastatin	Higher risk of muscle damage; some are paused during the course
Gout medicine	Colchicine	Risk of toxic levels, especially with kidney or liver problems
Blood thinners	Warfarin and others	Bleeding risk may change; extra monitoring needed
Heart rhythm-affecting medicines	Certain antiarrhythmics, some antipsychotics, some antidepressants	Increased risk of QT prolongation
Migraine medicines	Ergotamine and similar	Serious toxicity; usually must not be combined
Anti-clotting heart medicine	Ticagrelor	Levels can rise; usually avoided together
Seizure medicines	Carbamazepine, phenytoin	Levels can change
Sedatives	Midazolam and some similar medicines	Stronger and longer sedation
Other	Digoxin, theophylline, ciclosporin, tacrolimus	Blood levels may need monitoring

This list is not complete. If you take any regular medicine, ask your pharmacist to check the combination before your first dose.

What Clarithromycin 250 mg Is Prescribed For

• Chest infections: bacterial bronchitis flare-ups and community-acquired pneumonia
• Throat, sinus and ear infections: when a macrolide is appropriate, including when penicillin cannot be used
• Skin infections: certain mild to moderate bacterial cases
• Stomach ulcers linked to Helicobacter pylori: clarithromycin is one part of combination treatment alongside an acid-reducing medicine and another antibiotic
• Specialist uses: for example, some infections in people with weakened immunity, directed by a specialist

It does not treat colds, flu or other viral illnesses.

How Clarithromycin Is Usually Taken

Clarithromycin 250 mg is most often taken twice a day, around 12 hours apart, for a number of days chosen to match the infection. A typical course can run from about 5 to 14 days. For H. pylori, it is part of a regimen that usually lasts around 7 to 14 days, taken together with other medicines.

1. Follow your label exactly for the number of tablets and days.
2. Take doses about 12 hours apart, such as morning and evening.
3. Swallow whole with water. Food is optional; a meal can ease nausea.
4. Finish the full course unless a clinician tells you to stop.

Missed dose

Take it when you remember, unless the next dose is nearly due. Never take two doses at once to catch up.

Common Side Effects

• Altered or metallic taste, the side effect people mention most often with clarithromycin; it fades after the course
• Nausea, indigestion or stomach pain
• Loose stools or diarrhoea
• Headache
• Difficulty sleeping

Rare but important

• Severe or bloody diarrhoea: may signal a C. difficile infection
• Allergic reaction: rash, swelling, wheezing or trouble breathing (an emergency)
• Heart rhythm problems: palpitations, fainting or a fast irregular heartbeat
• Liver problems: yellow skin or eyes, dark urine, severe tiredness
• Hearing changes or ringing in the ears
• Muscle pain or weakness, especially if you also take a statin

Heart Health and Clarithromycin

Clarithromycin can lengthen the QT interval, and health regulators have also advised caution in people who already have heart disease. If you have a heart condition, a history of rhythm problems, or low potassium or magnesium, make sure your prescriber knows before starting. They may choose a different antibiotic instead.

Who Needs Extra Care

• People with heart disease or rhythm conditions
• People with liver or kidney disease, where doses may need adjusting
• People with myasthenia gravis, since macrolides can worsen weakness
• Anyone with a previous reaction to a macrolide such as erythromycin or azithromycin
• Pregnancy and breastfeeding: clarithromycin is generally avoided in pregnancy unless the prescriber decides the benefit outweighs the risk

Clarithromycin and Alcohol

Alcohol does not stop clarithromycin working, but it can worsen nausea and tiredness and add strain on the liver. Many clinicians recommend avoiding it during a course, especially if you have liver problems.

Clarithromycin vs Azithromycin and Amoxicillin

Antibiotic	Typical routine	Main contrast
Clarithromycin	Twice daily for several days	More drug interactions; metallic taste is common
Azithromycin	Once daily, often 3 to 5 days	Shorter course and fewer interactions in general
Amoxicillin	Two or three times daily	Penicillin family; not for penicillin allergy
Clindamycin	Several times daily	Often used for skin, dental and bone infections

They are not interchangeable. Your prescriber picks the one that fits the infection, your allergies and your other medicines.

Resistance and Responsible Use

Macrolide resistance has increased in several bacteria, which is why antibiotics should be used only when needed. Do not save leftovers, share tablets or ask for antibiotics for viral illnesses. The CDC’s antibiotic use pages explain how to protect these medicines.

Storage

• Keep tablets in the original pack, at room temperature, away from heat and damp.
• Keep out of reach of children.
• Do not use after the expiry date, and return unused tablets to a pharmacy.

Frequently Asked Questions

Why does clarithromycin leave a metallic taste?

Taste disturbance is a known and common effect. It is not harmful and usually clears soon after the course ends. Sugar-free sweets or gum may help.

How long does clarithromycin take to work?

Many people improve within two to three days. Contact your prescriber if you feel worse or see no change.

Can I take clarithromycin with a statin?

Some statins should be paused during a course. Ask your pharmacist or prescriber before taking both.

Can I take clarithromycin with food?

Yes. Food is optional and may reduce stomach upset.

Is clarithromycin safe in pregnancy?

It is usually avoided unless a prescriber decides it is necessary. Do not start or continue it without advice.

Why is it taken twice a day?

The medicine is cleared from the body over several hours, so two evenly spaced doses keep the level steady.

Can it treat a cold or the flu?

No. It only treats bacterial infections.

When should I get urgent help?

Seek emergency help for swelling of the face or throat, difficulty breathing, fainting, a very fast or irregular heartbeat, or a spreading blistering rash.

Where to Read More

Visit the NHS clarithromycin guide and the MedlinePlus clarithromycin entry.

Medical disclaimer: This information is for general education and does not replace advice from a qualified healthcare professional. Always follow your prescriber’s instructions and the leaflet supplied with your medicine.