What is Azithromycin?

Azithromycin is a prescription-only antibiotic used to treat a range of bacterial infections. It belongs to a group of medicines called macrolide antibiotics, which work by stopping bacteria from growing.

In travel medicine, azithromycin may be supplied as a standby treatment for moderate to severe traveller’s diarrhoea. When taken appropriately, it can help shorten the duration and reduce the severity of symptoms caused by certain bacterial infections.

Azithromycin does not treat viral infections.

What is Azithromycin Used For?

Treatment of bacterial infections, including:

Respiratory tract infections
Skin and soft tissue infections
Certain sexually transmitted infections
Moderate to severe traveller’s diarrhoea when bacterial infection is suspected

How Does Azithromycin Work?

Azithromycin works by interfering with bacterial protein production. This prevents bacteria from multiplying, allowing the body’s immune system to clear the infection more effectively.

When used for traveller’s diarrhoea, it targets common bacterial causes of infection and may help reduce symptom duration when started appropriately.

When Should I Use Azithromycin for Traveller’s Diarrhoea?

Azithromycin may be supplied as standby treatment to carry while travelling to higher-risk regions.

It should only be started if you develop more severe symptoms, such as frequent diarrhoea with fever, significant abdominal pain, blood in the stool, or symptoms that are disrupting your travel plans.

Mild diarrhoea often settles without antibiotics and can usually be managed with fluids and anti-diarrhoeal medication.

A clinician will assess your destination, medical history, and suitability before prescribing.

Who Can Use Azithromycin?

Adults (18+) travelling to moderate or high-risk regions
Those medically suitable for macrolide antibiotics
Individuals without known macrolide allergy

Who Should Not Use Azithromycin?

You should not take azithromycin if you:

Are allergic to azithromycin, erythromycin, or other macrolide antibiotics
Have previously experienced liver problems linked to azithromycin
Have certain heart rhythm conditions (such as known QT prolongation)
Are taking medicines that significantly affect heart rhythm
Have severe liver disease

A clinician will review your medical history and current medications to ensure it is safe for you.

Can I Get Azithromycin Without a Prescription?

No. Azithromycin is a prescription-only medicine (POM) in the UK.

It can be prescribed through a UK-registered online pharmacy after a clinician confirms it is appropriate for you and your travel plans.

Alternative Options for Traveller’s Diarrhoea

Oral rehydration salts
Loperamide for symptom control
Other antibiotics where clinically appropriate

Your clinician can advise whether standby treatment is suitable based on your destination and individual risk factors.

How to Take Azithromycin:

Take ONE 500 mg tablet once daily for 3 days

Swallow the tablet whole with water

It can be taken with or without food

Start treatment only if advised for severe traveller’s diarrhoea symptoms

Try to take it at the same time each day until the course is finished.

If you vomit within one hour of taking a dose, seek medical advice as you may need another dose.

If symptoms do not improve within 24 hours of starting treatment, or worsen at any time, seek medical help locally.

If you experience severe diarrhoea with signs of dehydration, persistent high fever, severe abdominal pain, or blood in the stool that does not improve, seek urgent medical attention.

Always read the patient information leaflet before use and follow the instructions carefully.

Active ingredient:

Azithromycin 500 mg (as azithromycin dihydrate)

Other ingredients (excipients):

May include lactose monohydrate, maize starch, sodium starch glycolate, magnesium stearate, hypromellose, titanium dioxide (E171), and other tablet coating agents.

Some brands of azithromycin tablets contain lactose.

Always check the patient information leaflet (PIL) for the full ingredient list, especially if you have allergies or lactose intolerance.
 
 
 

Common side effects:

Diarrhoea
Nausea
Mild Stomach pain or cramps
Headache
Vomiting

These are usually mild and settle after treatment finishes.

Less common:

Loss of appetite
Dizziness
Skin rash or itching
Changes in taste
Temporary changes in liver enzyme levels

Serious but rare:

Severe allergic reaction (anaphylaxis)
Severe or persistent diarrhoea (possible antibiotic-associated colitis)
Liver problems
Heart rhythm changes (QT prolongation)

Seek urgent medical help (999 / A&E) if you develop difficulty breathing, swelling of the face or throat, severe chest pain, fainting, or a severe skin reaction with blistering.

Seek medical attention promptly if you develop severe or persistent diarrhoea, particularly if it contains blood or mucus.

Contact your GP if side effects are persistent or concerning once you return to the UK.

Call NHS 111 if you’re unsure whether symptoms may be related to azithromycin.

Always read the patient information leaflet (PIL) for full safety and side-effect information.