Azithromycin

What is azithromycin?

Azithromycin is a widely used antibiotic that treats a variety of bacterial infections. It’s part of the macrolide group of antibiotics and is commonly prescribed under brand names such as Zithromax[1]. 

What is azithromycin used to treat?

Azithromycin is used to treat infections caused by bacteria sensitive to this type of antibiotic. These bacteria may sometimes cause[1]: 

• Chest infections (e.g. pneumonia or bronchitis) 

• Throat infections (e.g. tonsillitis) 

• Sinus infections 

• Ear infections 

• Skin infections 

• Some sexually transmitted infections like chlamydia 

• Dental infections 

How does azithromycin work?

Azithromycin works by preventing bacteria from making proteins that they need to grow and multiply. This stops the infection from spreading and allows your immune system to clear it from the body[1]. 

Who can take azithromycin?

Azithromycin is suitable for most adults and children. However, it may not be suitable for some people. Tell your doctor before taking it if you[1]: 

• Are allergic to azithromycin or any other macrolide antibiotics (e.g. erythromycin) 

• Have liver or kidney problems 

• Have a heart condition 

• Have diabetes 

• Are pregnant or breastfeeding (use only if advised by a doctor) 

• Have myasthenia gravis, a muscle-weakening condition, or porphyria, a rare inherited blood disorder 

Please tell your doctor or pharmacist about any conditions you may have or medication you take before you start treatment, and always follow the instructions in the Patient Information Leaflet[2].  

What is the usual dose of azithromycin?

The dose depends on the condition being treated. Azithromycin comes as either 250mg or 500mg tablets, 250mg capsules or 200mg in 5ml liquid[1].  

The usual dose is 500mg a day for 3 to 10 days depending on the infection, but this can vary from person to person and sometimes a higher dose is needed of 1g or 2g[1].  

Always follow your doctor’s instructions or the directions on the label. 

How do you take azithromycin?

Always follow your doctor or pharmacist’s instructions however, the usual dose is once each day. When taking the medication, try and take at the same time each day to ensure its effectiveness as you need to have a constant amount of drug in your body for it to work well. The tablets and capsules should be taken whole with a glass of water, with or without food. If you are using the liquid formulation, make sure to shake it well before use and to use a medicine spoon or oral syringe. Avoid using a kitchen spoon as this may not give you the right amount of medication[1]. 

Can you stop taking azithromycin early?

No – finish the full course, even if you feel better. Stopping early can lead to the infection returning and may increase the risk of antibiotic resistance[1]. 

What should you do if you take too much azithromycin?

Taking too much azithromycin may cause[1]: 

• Nausea 

• Diarrhoea 

• Hearing issues 

• Irregular heartbeat 

If you think you’ve taken too much, contact your GP, NHS 111, or go to A&E straight away if you experience severe symptoms. 

What to do if you forget a dose of azithromycin?

If you miss your dose, you should[1]: 

• Take it as soon as you remember 

• If it’s almost time for your next dose, skip the missed one 

• Do not take two doses at once to make up for a missed dose 

Medicines you can and can’t take with azithromycin

Azithromycin may interact with other medicines. Speak to your doctor or pharmacist before taking it if you also use[1]: 

• Antacids (containing aluminium or magnesium) – take azithromycin 1 hour before or 2 hours after 

• Warfarin – may increase bleeding risk 

• Digoxin – may increase levels of digoxin in your blood 

• Theophylline – may increase side effects 

• Statins – may increase the risk of muscle problems 

• Ergotamine or dihydroergotamine  

• Ciclosporin or tacrolimus – medicines to stop your immune system overreacting 

• Rifabutin, an antibiotic 

• Nelfinavir, HIV medicine  

Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[2]. 

What are the side effects of azithromycin?

The most common side effects include[1]: 

• Nausea 

• Diarrhoea 

• Stomach pain 

• Headache 

Serious side effects include[1]: 

• Allergic reactions (rash, swelling, breathing difficulties) 

• Liver problems (yellowing of the skin or eyes) 

• Irregular heartbeat 

You should contact your GP if you experience any of these symptoms. In rare cases, the medicine may cause a serious allergic reaction (anaphylaxis). You should call 999 or visit A&E immediately if you believe this is happening[1]. 

Symptoms of anaphylaxis include: 

• Difficulty breathing 

• Tightness in throat and chest 

• Swelling of the tongue or throat 

• Feeling faint or dizzy 

• Blue/grey skin or lips 

• Loss of consciousness 

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[2]. 

Frequently asked questions about azithromycin

Can I drink alcohol while taking azithromycin? 
Yes. Alcohol doesn’t directly interact with azithromycin, but it’s best to drink in moderation while recovering from an infection[1]. 

Can I take it with food? 
Yes, it can be taken with or without food[1]. 

How long does it take to work? 
You should start feeling better in a few days. Be sure to complete the full course[1]. 

Is azithromycin safe during pregnancy? 
It may be prescribed during pregnancy if your doctor thinks it’s necessary. Always take it under medical advice[1]. 

Will I get thrush while taking azithromycin? 

Antibiotics like azithromycin can kill the harmless bacteria that protect against thrush, so you may get that particular fungal infection. Speak to your doctor or pharmacist if you’re concerned[1]. 

For the official NHS guide for azithromycin, visit their website.