What is Zithromax used for?
Zithromax capsules and suspension contain the antibiotic azithromycin. Azithromycin is used to treat the following infections caused by bacteria:
- Bacterial infection of the lungs and airways (chest or lower respiratory tract infection) eg pneumonia, bronchitis.
- Bacterial infections of the nasal passages, sinuses or throat (upper respiratory tract infection) eg sinusitis, tonsillitis, pharyngitis.
- Bacterial infections of the middle ear (otitis media).
- Bacterial infections of the skin or soft tissue.
- Uncomplicated gonorrhoea.
- Mild or moderate typhoid due to multiple-antibacterial-resistant organisms (unlicensed use).
- Lyme disease (unlicensed use).
Viruses and bacteria
How does azithromycin work?
Azithromycin is a macrolide-type antibiotic. It works by preventing bacteria from producing proteins that are essential to them. Without these proteins the bacteria cannot grow, replicate and increase in numbers. Azithromycin therefore stops the spread of infection and remaining bacteria are killed by the body's immune system or eventually die.
Azithromycin is a broad-spectrum antibiotic, which means it is active against a wide variety of bacteria that cause a wide variety of infections. Azithromycin may be used to treat infections of the upper or lower airways, skin or soft tissue, or ears. It is also used to treat the sexually-transmitted infection chlamydia.
To make sure the bacteria causing an infection are susceptible to azithromycin your doctor may take a tissue sample, for example a swab from the throat or skin.
Microscopy and culture
How do I take Zithromax?
- The dose of this medicine and how long it needs to be taken for depends on the type of infection you have and your age. Follow the instructions given by your doctor. These will be printed on the dispensing label that your pharmacist has put on the packet of medicine.
- Azithromycin is usually taken once a day. Try and take it at the same time each day.
- For the treatment of chlamydia only one dose is needed.
- Zithromax capsules should be taken at least one hour before or two hours after food.
- Zithromax suspension can be taken either with or without food.
- Bottles of suspension should be shaken before measuring out a dose. Only use the measuring spoon provided with the suspension. You should not use a regular teaspoon or tablespoon to take the medicine, as this will not give an accurate dose.
- Do not take indigestion remedies at the same time of day as azithromycin. This is because indigestion remedies can affect the absorption zithromax of azithromycin from the gut.
- If you forget to take a dose take it as soon as you can that day. Then take your next dose at the right time the following day. Do not take a double dose to make up for a missed dose.
- Unless your doctor tells you otherwise, it is important that you finish the prescribed course of this antibiotic medicine, even if you feel better or it seems the infection has cleared up. Stopping the course early increases the chance that the infection will come back and that the bacteria will grow resistant to the antibiotic.
Treatments for sexually transmitted infections
Things to know about Zithromax before taking?
- Broad-spectrum antibiotics can sometimes cause inflammation of the bowel (colitis). For this reason, if you get diarrhoea that becomes severe or persistent or contains blood or mucus, either during or after taking this medicine, you should consult your doctor immediately.
- All antibiotics can sometimes result in overgrowth of organisms that are not susceptible to the antibiotic, in particular fungi. You should let your doctor know if you think you have developed any other infection, for example thrush, while you are taking this medicine, so that it can be treated appropriately.
- Zithromax suspension can be stored at room temperature. Any suspension remaining after 5 days should be disposed of, preferably by returning it to your pharmacist.
Who should not take Zithromax?
- Children under six months of age.
- People who are allergic to other macrolide or ketolide type antibiotics, eg erythromycin, clarithromycin.
- Zithromax capsules are not suitable for children weighing under 45kg. The suspension should be used for children who weigh under 45kg.
- Zithromax capsules contain lactose and are not suitable for people with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Zithromax should be used with caution in
- People with severely decreased kidney function.
- People with liver disease (azithromycin should be avoided where possible in people with severe liver disease).
- People with heart problems such as heart failure or irregular heartbeats (arrhythmias).
- People with a very slow heartbeat (bradycardia).
- People with an abnormal heart rhythm seen on a heart monitoring trace (ECG) as a 'prolonged QT interval'.
- People taking medicines that can prolong the QT interval (your doctor will know, but see the end of this factsheet for some examples).
- People with disturbances in the levels of electrolytes such as potassium and magnesium in their blood.
- People with a condition called myasthenia gravis, where there is abnormal muscle weakness.
- People with diabetes should be aware that Zithromax suspension contains sucrose. For this reason it may also not be suitable for people with hereditary problems of fructose intolerance.
Can I take azithromycin while pregnant or breastfeeding?
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of azithromycin for use during pregnancy has not been established. It is not recommended for use in pregnancy unless considered essential by your doctor. Ask you doctor for further medical advice.
- Azithromycin passes into breast milk. It is not recommended for use during breastfeeding unless considered essential by your doctor. Seek medical advice from your doctor.
What are the possible side effects of azithromycin?
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
Very common (affect more than 1 in 10 people)
- Disturbances of the gut such as diarrhoea, nausea, abdominal pain or wind.
Common (affect between 1 in 10 and 1 in 100 people)
- Loss of appetite.
- Pins and needles sensations (paraesthesia).
- Pain in the joints (arthralgia).
- Rash or itching.
- Taste disturbances.
- Disturbances in vision or hearing.
Uncommon (affect between 1 in 100 and 1 in 1000 people)
- Feeling weak or generally unwell.
- Oral or vaginal thrush infections (candidiasis - see important information above).
- Inflammation of the stomach (gastritis).
- Difficulty sleeping (insomnia).
- Reduced sensation or numbness (hypoaesthesia).
- Increased sensitivity of the skin to sunlight.
- Nervousness or anxiety.
- Awareness of your heartbeat (palpitations).
- Chest pain.
- Swelling due to fluid retention (oedema).
- Inflammation of the liver (hepatitis). Symptoms that may suggest a liver problem include persistent nausea and vomiting, abdominal pain, or the development of jaundice (a yellow colouring to the skin and the whites of the eyes). Consult your doctor if you experience any of these symptoms while taking this medicine.
- Decrease in the number of white blood cells in the blood.
Vaginal thrush (female candidiasis)
Rare (affect between 1 in 1000 and 1 in 10,000 people)
- Sensation of spinning (vertigo).
- Abnormal liver function.
Talk to your doctor, nurse or pharmacist if you want any more information about the possible side effects of this medicine. If you think you have experienced a side effect, did you know you can report this using the yellow card website?
Can I take azithromycin with other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
Is it dangerous to take different medicines at the same time?
This medicine should not be taken by people taking ergotamine or related medicines, eg dihydroergotamine or methysergide (used to treat migraine).
Antacids for indigestion and heartburn reduce the absorption of azithromycin from the gut if they are taken at the same time as azithromycin. Azithromycin should be taken at least one hour before or two hours after taking an antacid.
Azithromycin may reduce the breakdown of the medicines listed below. If the blood levels of these medicines are raised as a result, it may lead to an increased risk of their side effects. If you are taking one of these medicines and are prescribed azithromycin you should let your doctor or pharmacist know if you experience any new or increased side effects:
If you are taking digoxin or ciclosporin it is recommended that your blood levels of these medicines are monitored while you are taking a course of azithromycin. Your doctor may adjust your digoxin or ciclosporin dose if necessary.
The manufacturers of droperidol, mizolastine, pimozide and reboxetine state that macrolide antibiotics such as this one are not recommended for people taking these medicines.
Azithromycin may enhance the anti-blood-clotting effects of warfarin and possibly other anticoagulant medicines. If you are taking an anticoagulant your doctor may want to perform extra monitoring of your blood clotting time (INR) while you are also taking azithromycin.
There may be a risk of a drop in the numbers of white blood cells in the blood if azithromycin is used in combination with rifabutin.
Oral typhoid vaccine (Vivotif) should not be taken until at least three days after you have finished a course of this antibiotic, because the antibiotic could make the vaccine less effective.
Nelfinavir may increase the amount of azithromycin in the blood. If you regularly take nelfinavir you should tell your doctor if you experience any new side effects while taking a course of azithromycin.
There may be an increased risk of abnormal heart beats if azithromycin is taken in combination with other medicines that can affect the heart rhythm (prolonged QT interval on an ECG), such as the following:
- arsenic trioxide
- certain medicines to treat abnormal heartbeats (antiarrhythmics), eg amiodarone, procainamide, quinidine, disopyramide, sotalol, dronedarone
- certain antidepressants, eg citalopram, escitalopram, clomipramine
- certain antipsychotics, eg haloperidol, chlorpromazine, sertindole, thioridazine, pimozide, amisulpride, quetiapine
- certain antimalarials, eg quinine, mefloquine, chloroquine, Riamet
- certain other anti-infectives, eg clarithromycin, telithromycin, voriconazole, pentamidine, moxifloxacin
In the past, women using hormonal contraception such as the pill or patch would be advised to use an extra method of contraception (eg condoms) while taking an antibiotic like this one and for seven days after finishing the course. However, this advice has now changed. You no longer need to use an extra method of contraception with the pill, patch or vaginal ring while you take a course of antibiotics. This change in advice comes because to date there is no evidence to prove that antibiotics (other than rifampicin or rifabutin) affect these contraceptives. This is the latest guidance from the Faculty of Sexual & Reproductive Healthcare.
However, if you are taking the contraceptive pill and experience vomiting or diarrhoea as a result of taking this antibiotic, you should follow the instructions for vomiting and diarrhoea described in the leaflet provided with your pills.
Other medicines containing azithromycin
Azithromycin capsules, tablets and suspension are also available without a brand name, ie as the generic medicine.
Branded and generic medicines
For background information about our medicine factsheets, including the references used to produce them, click here.
Last updated 27.04.2015
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