• Clarithromycin is used for the treatment of infections including those of the chest, skin and ear. It is also used for some types of stomach ulcer.
  • Even if your condition improves, it is important to complete the prescribed course unless you are told to stop. Otherwise your infection could come back.
  • Any side-effects are usually mild. The most common are feeling or being sick, indigestion, and diarrhoea.
Type of medicine Macrolide antibiotic
Used for Bacterial infections including chest, skin, and ear infections
Some types of stomach ulcers
Also called Clarie® XL
Klaricid® XL
Available as Tablets, oral liquid, sachet, modified-release tablets, and injection

Clarithromycin is used to treat a variety of bacterial infections. It works by killing the bacteria that cause the infection.

Before taking clarithromycin make sure your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have liver or kidney problems.
  • If you have heart rhythm problems.
  • If you are taking other medicines, including those available to buy without a prescription, herbal and complementary medicines.
  • If you have ever had an allergic reaction to this or any other medicine.
  • Before starting this treatment, read the manufacturer's printed information leaflet from inside the pack.
  • Take clarithromycin exactly as your doctor has told you. If you have been told to make more than one dose a day, space your doses evenly throughout the day.
  • For most forms of clarithromycin, it is not important whether you take your doses before, with or after food. If however you have been given Klaricid® XL or Clarie® XL, you should take these just after a meal or snack.
  • If you have been given clarithromycin sachets, mix the granules from the sachet into a small glass of water before taking.
  • Keep taking this antibiotic until the course is finished unless you are told to stop. It is important to take the full course (even if you feel your infection has cleared up) to prevent the infection from coming back.
  • If you forget to take a dose, take it as soon as you remember and then continue as before. Do not take two doses together to make up for a forgotten dose.
  • If you still feel unwell after completing your course of this antibiotic, make another appointment to see your doctor.
  • Some people develop thrush (redness and itching in the mouth or vagina) after taking a course of antibiotics. If you think you have thrush speak with your doctor or pharmacist for advice.
  • If you are using oral combined hormonal contraception (the 'pill'), additional contraceptive precautions such as condoms are not required during a course of this antibiotic unless you are sick or have diarrhoea. If you need further advice, speak with your doctor or pharmacist.
  • If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking clarithromycin.
  • This antibiotic may stop the oral typhoid vaccine from working. If you are having any vaccinations, make sure the person treating you knows that you are taking this medicine.
  • If you buy any medicines, check with a pharmacist that they are safe to take with this antibiotic.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common side-effects - these affect less than 1 in 10 people who take this medicine What can I do if I experience this
Feeling or being sick, stomach ache, wind, and indigestion Eat little and often and stick to simple or bland foods
Diarrhoea Drink plenty of water to replace lost fluids. If the diarrhoea continues or is severe, see your doctor or pharmacist for advice
Tooth or tongue discolouration and changes in the way things taste or smell This will disappear after you finish your treatment
Sore throat with inflamed gums, lips or tongue Speak with your doctor if this becomes a problem
Headache Ask your pharmacist to recommend a suitable painkiller. If the headache continues, speak with your doctor

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.
  • Do not use clarithromycin after the expiry date shown on the label.

  • Never take more than the prescribed dose. If you suspect that you or someone else has taken an overdose of this medicine go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.
  • Always read the printed information leaflet that comes with your medicine.
  • This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
  • Never keep out of date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
  • If you have any questions about this medicine ask your pharmacist.

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Last Checked:
Document ID:
3421 (v24)
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