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Terms Of Use


Brand Name(s) : Klaricid, Klaricid IV, Klaricid XL
Side Effects


Clarithromycin should be used with caution in: pregnant women and women who are breastfeeding, those with liver or kidney problems, myasthenia gravis, and coronary heart disease.

It should not be used in: people allergic to clarithromycin or to any ingredient in the medicine, or in people with severe liver failure.

Also see list of precautions and interactions.


Store in a dry place and protect from light. Store below 25°C.


What is it used for?

  • Clarithromycin is used to treat a number of problems.
  • It is a macrolide antibacterial drug, sometimes known as an antibiotic.
  • It is used to treat infections caused by bacteria in many different parts of the body.
  • In general this drug is used to treat infections of the respiratory tract, middle ear, skin (and underlying soft tissue, such as muscle), and the healing of duodenal ulcers (when given alongside other drugs) by eradicating the bacteria (Helicobacter pylori) that cause these ulcers.
  • Benefits of being on this drug can include eradication and resolution of bacterial infections, allowing recovery and relief of symptoms such as pain or cough caused by the infection.

Listed below are the typical uses of clarithromycin.

  • Treatment of bronchitis (inflammation of the air passages in the lungs owing to a bacterial infection)
  • Treatment of pneumonia (inflammation of the lungs owing to a bacterial infection)
  • Treatment of sinusitis (inflammation of the sinuses which are air-filled cavities in the bones of the face that improve the resonance of the voice, often owing to a bacterial infection)
  • Treating throat infections such as pharyngitis (infection of the pharynx, which is the area of the throat and neck behind the nose and mouth) or tonsillitis (infection of the tonsils, which are areas of soft tissue at both sides of the throat)
  • Otitis media (infection of the middle ear)
  • Skin and soft tissue infections (such as an abscess or boils).

On occasion your doctor may prescribe this medicine to treat a condition not on the above list.


How often do I take it?

  • Take this medication by mouth, usually twice daily, with or without food. Tablets may be swallowed with water. It is also available as a powder to be suspended in water and taken by mouth, and this can be taken with food. Clarithromycin is also available in liquid form for intravenous use when given by a doctor or another healthcare professional.
  • Use this medication for the duration of the prescription in order to get the most benefit from it.
  • Remember to use it at the same time each day - unless specifically told not to by your doctor.
  • It may take some time before the full benefit of this drug takes effect.
  • Certain medical conditions may require different dosage instructions as directed by your doctor.

What dose?

  • Dosage is based on your age, gender, medical condition, response to therapy, and use of certain interacting medicines.

Do I need to avoid anything?

  • Clarithromycin may make you feel confused, disorientated or dizzy. Do not drive or operate machinery if you are affected. Consult your doctor or pharmacist for more details.

When can I stop?

  • Always complete the full course as prescribed by your doctor.


If any of these persist or you consider them severe then inform your doctor or pharmacist.

Tell your doctor immediately if you develop any of the following symptoms: changes in heartbeat, chest pain, convulsions (fits), severe or prolonged diarrhoea, or yellowing of the skin or eyes (jaundice).

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

The Yellow Card Scheme allows you to report suspected side effects from any type of medicine (which includes vaccines, herbals and over the counter medicines) that you are taking. It is run by the medicines safety watchdog called the Medicines and Healthcare products Regulatory agency (MHRA). Please report any suspected side effect on the Yellow Card Scheme website.


Before taking clarithromycin, tell your doctor or pharmacist if you are allergic to it; or to other antibiotics; or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist in case of: severe liver problems.

Before using this medication tell your doctor or pharmacist your medical history, especially any of the following: any kidney or liver problems, myasthenia gravis, and coronary heart disease.

Before having surgery, tell your doctor or dentist that you are taking this medication.

Does alcohol intake affect this drug?

  • It is not known whether drinking alcohol affects this drug's action.

The elderly: clarithromycin can be used in the elderly.

Pregnancy and breastfeeding - please ensure you read the detailed information below


Clarithromycin is not safe to take if you are, or are planning to become, pregnant.

It is sensible to limit use of medication during pregnancy whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.


Clarithromycin is not safe to take if you are breastfeeding.

It is sensible to limit use of medication during breastfeeding whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.


Before using this medicine, tell your prescriber of all the medicines you are taking including prescription medicines and medicines you have bought over the counter without a prescription. Tell your prescriber if you are taking vitamins or complementary remedies such as herbal products, as these can also interact with medicines.

If you are taking more than one medicine, these may interact with each other. Your prescriber may decide to use medicines which interact with each other if the benefit outweighs the risks. In these cases, the dose of your medicines may need to be adjusted or you may be monitored more closely.

The following medicines may interact with clarithromycin:

  • Ergot derivatives or ergotamine, used to treat migraine
  • Cisapride
  • Pimozide
  • Terfenadine
  • Astemizole
  • Lipid-regulating drugs (e.g. simvastatin)
  • Sirolimus, used as an immunosuppressant.
  • Eletriptan, used to treat migraine
  • Ivabradine, used to treat angina
  • Diuretics (eplerenone)
  • Antihistamines (mizolastine)
  • Nilotinib, used to treat leukaemia
  • Other antibiotics (rifabutin or rifampicin)
  • Anti-arrhythmics (e.g. digoxin or disopyramide)
  • Blood-thinning drugs (e.g. warfarin)
  • Antidiabetics (repaglinide)
  • Anti-epileptics (e.g. carbamazepine or phenytoin)
  • Antivirals (e.g. marviroc, ritonavir, tipranavir or zidovudine)
  • Sedatives (e.g. midazolam or triazolam)
  • Immunosuppressants (e.g. ciclosporin or tacrolimus)
  • Lipid-regulating drugs (e.g. atorvastatin or pravastatin)
  • Colchicine, used to treat gout
  • Terfenadine, used to treat hay fever or a skin allergy
  • Tolterodine, used to treat urinary incontinence
  • Theophylline, used to treat asthma

This information does not contain all possible interactions. Therefore, tell your prescriber of all the products you are using before taking this medicine.

If you have a question or want to discuss anything about your medicine, speak to your local pharmacist.


Taking too much clarithromycin may cause the following: feeling sick (nausea), vomiting and diarrhoea, as well as altered mental states such as confusion.

People who have taken too much clarithromycin should seek assistance from a healthcare professional.

If you think you, or someone you care for, might have accidentally taken more than the recommended dose of clarithromycin or intentional overdose is suspected, contact your local hospital, GP or if in England call 111. In Scotland call NHS 24. In Wales, call NHS Direct Wales. In the case of medical emergencies, always dial 999.


If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

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Source: Selected from data included with permission and copyrighted by Boots UK Limited. This copyrighted material is sourced from a licensed data provider and is not for distribution, except as may be authorised by the applicable terms of use.
CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgement of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse events, nor should it be construed to indicate that use of a particular medicine is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any medicine, changing any diet, or discontinuing any course of treatment.

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