Zithromax (Azithromycin)

Azithromycin is a macrolide antibiotic prescribed for certain infections caused by susceptible bacteria, including some respiratory tract infections, ear infections, skin infections and specific sexually transmitted infections (STIs). It works by stopping bacteria from making the proteins they need to grow, which slows bacterial growth. In Australia, it is used in routine general practice and sexual health care when a clinician considers it appropriate. Many treatment courses are short because azithromycin stays in the body longer than some other antibiotics.

Top 10 antibiotics

The list below highlights commonly prescribed antibiotics used across many healthcare settings.

1. Amoxicillin - One of the most commonly prescribed antibiotics in many settings.
2. Cephalexin - A common option for certain skin and soft tissue infections and other susceptible infections.
3. Amoxicillin/Clavulanate (Augmentin) - A combination antibiotic used when beta-lactamase-producing bacteria are a concern.
4. Doxycycline - A broad-spectrum antibiotic used for a range of infections, including some respiratory infections and acne.
5. Ciprofloxacin - A fluoroquinolone used for specific infections; it can carry serious risks and should only be used when appropriate.
6. Trimethoprim - Often used for urinary tract infections (note: some products/regions use combination therapy).
7. Flucloxacillin - A penicillin antibiotic mainly used for skin infections and commonly used in Australia and the UK.
8. Clindamycin - Used for selected infections, including some anaerobic and skin infections.
9. Metronidazole - A go-to option for anaerobic infections and certain protozoal infections.
10. Azithromycin - A useful option for selected respiratory infections and certain STIs when clinically appropriate.

How azithromycin compares with other commonly prescribed antibiotics

Detailed comparisons of azithromycin with other antibiotics

Azithromycin vs. Amoxicillin

Azithromycin covers susceptible bacteria and is active against atypical organisms such as Mycoplasma pneumoniae. It is sometimes chosen when penicillin allergy is a concern. Depending on the condition and local resistance patterns, amoxicillin may be preferred for some common infections, such as acute otitis media. Both medicines can cause gastrointestinal side effects. Azithromycin has been associated with QT interval prolongation and should be used with caution in at-risk patients.

Azithromycin vs. Augmentin (Amoxicillin/Clavulanate)

While both antibiotics are used for certain respiratory infections, Augmentin has stronger activity against some beta-lactamase-producing bacteria because of clavulanate. Azithromycin is more active against atypical pathogens and is often used in shorter treatment courses. Augmentin, however, is more likely to cause gastrointestinal side effects.

Azithromycin vs. Cephalexin

Cephalexin mainly targets Gram-positive bacteria and is often used for skin and soft tissue infections. Azithromycin's activity against atypical pathogens makes it useful for selected respiratory infections and certain STIs. While both antibiotics are generally well tolerated, azithromycin usually requires fewer doses because of its longer half-life.

Azithromycin vs. Doxycycline

Doxycycline is effective against many infections, including acne and tick-borne illnesses, whereas azithromycin is commonly used for selected respiratory infections and certain STIs. Doxycycline is generally avoided in younger children because it can affect developing teeth, although short courses are used for certain serious infections. Azithromycin may be used in children when appropriate; follow a clinician's advice.

Azithromycin vs. Ciprofloxacin

Ciprofloxacin is a fluoroquinolone with strong activity against Gram-negative bacteria and is used for specific infections. Azithromycin, by contrast, is often chosen for selected respiratory infections and certain STIs. Fluoroquinolones can carry serious risks, including tendon injury; the choice depends on the infection, susceptibility results when available, and individual patient factors.

Azithromycin vs. Trimethoprim

Trimethoprim is mainly used for urinary tract infections, whereas azithromycin is used for different infections. They work in different ways, with trimethoprim inhibiting folic acid synthesis and azithromycin targeting protein synthesis. Trimethoprim may cause skin reactions in some patients, while azithromycin is more commonly linked with gastrointestinal upset.

Azithromycin vs. Flucloxacillin

Flucloxacillin is mainly used for infections caused by Staphylococcus aureus, especially skin infections. Azithromycin works against a broader range of susceptible organisms but may be less effective against some resistant Gram-positive bacteria. Both antibiotics can cause mild gastrointestinal side effects.

Azithromycin vs. Clindamycin

Clindamycin is often chosen for anaerobic infections and some dental infections, while azithromycin is better suited to selected respiratory infections and certain STIs. Clindamycin carries a higher risk of C. difficile-associated diarrhoea, and any antibiotic-associated diarrhoea should be checked by a clinician.

Azithromycin vs. Metronidazole

Metronidazole is highly effective against anaerobic bacteria and protozoa, whereas azithromycin is used for selected respiratory infections and certain STIs. Metronidazole can cause a metallic taste and gastrointestinal upset; alcohol should generally be avoided during metronidazole treatment. Azithromycin has different interaction and dietary considerations depending on the product and the patient.

Advantages of azithromycin

1. Effective for certain bacterial infections, including selected respiratory infections and some sexually transmitted infections.
2. Used in Australia for a range of infections caused by susceptible bacteria, including chlamydia and some respiratory infections, depending on the product information and clinical indication.
3. Works by inhibiting bacterial protein synthesis, which can be useful against intracellular pathogens.
4. Often given as a short-course treatment because of its long half-life, which may help support adherence.
5. It is often well tolerated; however, side effects, drug interactions and risks vary from person to person.

Contraindications and precautions by age group

General contraindications (all ages)

Before looking at age-related considerations, it is important to distinguish true contraindications from warnings and precautions.

Allergic reactions

Azithromycin is contraindicated in people with known hypersensitivity to azithromycin, erythromycin, any macrolide, or any ketolide antibiotic. Allergic reactions can range from a rash to severe anaphylaxis.

Hepatic dysfunction related to prior azithromycin use

Azithromycin is contraindicated in patients with a history of cholestatic jaundice or hepatic dysfunction associated with previous azithromycin use.

Heart rhythm risk (QT prolongation)

QT prolongation and torsades de pointes have been reported with azithromycin. Consider this risk when prescribing for patients with known QT prolongation, a history of torsades de pointes, congenital long QT syndrome, bradyarrhythmias or uncompensated heart failure, uncorrected hypokalaemia or hypomagnesaemia, clinically significant bradycardia, or when it is used with other QT-prolonging medicines.

Myasthenia gravis

Worsening of myasthenia gravis symptoms and new onset of myasthenic syndrome have been reported with azithromycin. Patients with myasthenia gravis should use azithromycin only under a clinician's guidance.

Liver and kidney issues

Azithromycin has been associated with hepatotoxicity, including rare severe outcomes. Stop taking it and seek medical care if symptoms of hepatitis occur, such as jaundice, dark urine, right upper abdominal pain or marked fatigue. Renal impairment: dose adjustment is not routinely required in mild to moderate impairment; use caution in severe renal impairment.

Neonates (0-42 days)

Following the use of azithromycin in neonates (treatment up to 42 days of life), infantile hypertrophic pyloric stenosis (IHPS) has been reported. Parents and carers should contact a clinician if vomiting or irritability with feeding occurs.

Infants and toddlers (43 days to 2 years)

Azithromycin may be prescribed in this age group when clinically appropriate, but in Australia the choice of treatment should be guided by the type of infection, local resistance patterns and available first-line options. Carers should seek medical advice promptly if significant vomiting, persistent diarrhoea, rash or signs of an allergic reaction occur.

Children (2-16 years)

Children may experience gastrointestinal side effects, including diarrhoea and vomiting. Rarely, hearing-related side effects have been reported, particularly with prolonged courses or in patients with significant underlying illness. Azithromycin should be chosen for common infections in line with a clinician's advice and local recommendations, including when first-line agents are not suitable because of allergy or other factors.

Additionally, children with myasthenia gravis may experience worsening symptoms. Long-term or repeated use can contribute to antibiotic resistance.

Adolescents and adults

Most adolescents and adults tolerate azithromycin well. However, extra caution is needed in the following situations:

1. Heart rhythm risk: azithromycin may increase the risk of arrhythmias, particularly in patients with prolonged QT syndrome or when combined with other QT-prolonging medicines.
2. Liver disease or prior cholestatic jaundice related to azithromycin: prior cholestatic jaundice/hepatic dysfunction associated with azithromycin is a contraindication; other liver disease needs careful clinician oversight.
3. History of antibiotic-associated diarrhoea: Clostridioides difficile-associated diarrhoea (CDAD) can occur with nearly all antibiotics; seek care for severe or persistent diarrhoea.
4. Diabetes: some liquid formulations may contain sugar, so patients may need to account for carbohydrate intake as advised.
5. Myasthenia gravis: symptoms may worsen.
6. Pregnancy and breastfeeding: use only if clearly indicated. Discuss breastfeeding considerations with a clinician.
7. Drug interactions: azithromycin can interact with other medicines, including certain antiarrhythmics and anticoagulants.

Elderly patients (65 years and older)

Older adults may be more vulnerable to QT-related effects and possible drug interactions, especially when taking multiple medicines. Azithromycin should be used cautiously in patients with cardiac risk factors and when combined with QT-prolonging medicines. Gastrointestinal side effects may also be more troublesome for some older people.

While no specific routine dose adjustment is required solely on the basis of age, clinicians should consider comorbidities, concomitant medicines and overall risk, including cardiovascular risk.

Special considerations

Limitations of use (pneumonia/oral therapy): oral azithromycin should not be used for pneumonia in patients considered unsuitable for oral therapy because of moderate to severe illness or certain risk factors, such as cystic fibrosis, nosocomial infection, known or suspected bacteraemia, a need for hospitalisation, or significant underlying health problems such as immunodeficiency or functional asplenia.

Dosing: dosing depends on the infection being treated, age/weight and formulation. Use only the regimen prescribed by your clinician, and complete the course as directed unless your prescriber tells you otherwise.

Azithromycin is an effective antibiotic when used appropriately, but age-related risks and individual medical conditions should be considered before use. If you or a loved one are considering azithromycin treatment, speak with a healthcare professional to find out whether it is suitable for the specific age group and clinical situation.

Azithromycin and antibiotic resistance

How resistance to azithromycin develops

Bacteria can become resistant to azithromycin through several mechanisms. One common pathway is mutation and selection, where bacteria with genetic changes that reduce susceptibility survive antibiotic exposure and continue to multiply.

Resistance can also occur through efflux pumps, which reduce the amount of antibiotic inside the bacterial cell. In addition, bacteria may alter the antibiotic's target site, the ribosome, so azithromycin binds less effectively. Some bacteria can inactivate macrolides through enzymatic mechanisms.

Widespread and inappropriate use of azithromycin, such as using it for viral illnesses or not taking it as prescribed, can speed up the development and spread of resistant strains.

Consequences of azithromycin resistance

Rising resistance can make infections harder to treat. Patients may need alternative antibiotics, which may be less convenient, more expensive or linked with different side effects. Resistance can contribute to prolonged illness and a higher risk of complications.

Healthcare systems may also face higher costs when resistant infections lead to extra clinic visits, hospitalisation or more intensive care.

Azithromycin resistance in common infections

Resistance to azithromycin has been reported in multiple settings. In respiratory tract infections, reduced susceptibility has been seen in pathogens such as Streptococcus pneumoniae and Haemophilus influenzae, which can contribute to treatment challenges depending on local resistance patterns.

For Neisseria gonorrhoeae, increasing azithromycin resistance has been documented, and many guidelines have moved away from routine azithromycin co-therapy in part because of antimicrobial stewardship and resistance concerns.

In gastrointestinal infections, increasing resistance in organisms such as Campylobacter has been reported in some regions, which can complicate treatment decisions.

Strategies to prevent azithromycin resistance

Reducing resistance requires careful, responsible antibiotic use. Azithromycin should only be used when a clinician decides it is appropriate for a suspected or confirmed bacterial infection, taking local guidance and resistance patterns into account. Completing the course exactly as prescribed helps reduce the chance that partly susceptible bacteria survive and spread.

Clinicians should avoid prescribing antibiotics for viral infections such as the common cold and flu, where antibiotics do not help.

Surveillance and research are important for tracking resistance trends, guiding prescribing practices and supporting the development of new antimicrobial strategies.

Global measures to slow antibiotic resistance

Many countries support antibiotic stewardship and antimicrobial resistance (AMR) surveillance programs to reduce inappropriate antibiotic use and track resistant strains.

Globally, the World Health Organization's Global Antimicrobial Resistance and Use Surveillance System (GLASS) supports standardised collection and sharing of AMR data.

The future of azithromycin and resistance

Growing resistance highlights the need for continued antibiotic stewardship, surveillance and innovation. Researchers are evaluating new antibiotics and alternative approaches, but many options are still under investigation and are not routine treatments.

Azithromycin remains an important antibiotic when used appropriately. Patients and healthcare providers can help preserve its effectiveness by using antibiotics only when needed, following prescribed directions, and supporting evidence-based stewardship efforts.

Interactions with Azithromycin

Overview of Azithromycin Interactions

Azithromycin can interact with certain medicines and may need extra caution in some medical conditions. While azithromycin is generally less likely to cause some enzyme-mediated interactions than certain other macrolides, clinically important interactions can still happen, especially in people taking multiple medicines.

Disease Interactions

Azithromycin has known disease interactions that need caution, including:

1. QT prolongation - a higher risk in people with a history of QT prolongation or those taking medicines that affect heart rhythm.
2. Liver disease - liver side effects have been reported; people with liver impairment may need closer monitoring.
3. Myasthenia gravis - azithromycin may worsen symptoms of this neuromuscular disorder.
4. Colitis (Clostridioides difficile) - antibiotics can disrupt normal gut flora and increase the risk of C. difficile-associated diarrhoea.

For more information, visit our article on precautions and contraindications for different age groups.

Common Drug Interactions

• Nelfinavir - may increase azithromycin serum concentrations; monitor for side effects.
• Warfarin and other oral anticoagulants - may increase anticoagulant effects; monitor INR/prothrombin time.
• Digoxin, colchicine, or phenytoin - careful monitoring is advised when used with azithromycin.
• Antacids (aluminium- or magnesium-containing) - may reduce absorption; separate dosing (for example, by at least 2 hours).
• Ergotamine or dihydroergotamine - avoid using them together unless specifically advised by a clinician.
• Cyclosporine or tacrolimus - monitoring may be needed; clinicians may adjust treatment based on levels and clinical response.
• Rifabutin - may need monitoring when used together.
• Statins - seek medical advice if you develop unexplained muscle pain, tenderness, or weakness.
• Heart rhythm medicines and other QT-prolonging drugs - using azithromycin with QT-prolonging medicines may increase the risk of arrhythmias.

Comparing with Other Antibiotics

Understanding how azithromycin compares with other antibiotics in terms of effectiveness and safety can help you choose the most suitable treatment option.

Azithromycin and Herbal Remedies and Supplements

Information on interactions between azithromycin and herbal remedies or supplements is limited. Always tell your clinician or pharmacist about any supplements, vitamins, or herbal products you use.

OTC Medications

Common OTC medicines such as paracetamol, loratadine and cetirizine are generally considered compatible for many people. However, ask an Australian clinician or pharmacist if you use decongestants, antacids, or any medicine that can affect heart rhythm.

Azithromycin and Food

Azithromycin tablets and immediate-release oral suspension are typically taken with or without food. The extended-release suspension (Zmax) should be taken on an empty stomach (at least 1 hour before or 2 hours after a meal). Taking immediate-release forms with food may help reduce stomach upset for some people.

Azithromycin and Drinks

There is limited evidence that specific drinks meaningfully change how well azithromycin works for most people. If azithromycin upsets your stomach, taking the immediate-release forms with a small meal may help.

Azithromycin and Alcohol

There is no specific Australian warning that prohibits drinking alcohol with azithromycin, but alcohol can worsen nausea, diarrhoea and dehydration. It's generally sensible to limit alcohol while you're unwell or taking antibiotics.

Precautions and Additional Considerations

Tell your clinician about all the medicines you take, especially those that affect heart rhythm or are known to interact with macrolide antibiotics.

Live oral cholera vaccine (VAXCHORA): do not give VAXCHORA to patients who have received oral or parenteral antibiotics within 14 days before vaccination.

Side Effects of Azithromycin

Common Side Effects

Azithromycin may cause some common side effects. If these symptoms bother you or do not go away, speak to your healthcare provider:

• nausea (feeling sick);
• vomiting (being sick);
• diarrhoea;
• stomach pain;
• loss of appetite;
• headaches;
• dizziness or fatigue;
• changes in taste.

Serious Side Effects

Although less common, azithromycin can cause serious side effects. Get medical attention if you experience any of the following:

Severe Allergic Reactions

Stop taking the medicine and get immediate medical help if you experience:

• difficulty breathing or wheezing;
• a rapid heartbeat;
• fever or feeling generally unwell;
• swollen lymph nodes;
• swelling of the face, lips, mouth, tongue, or throat;
• difficulty swallowing or throat tightness;
• skin rash, itching, or hives;
• dizziness, light-headedness, or fainting.

Angioedema

Azithromycin may cause swelling of the lips, face, tongue, or throat. Stop taking the medicine and contact your doctor if swelling occurs. If breathing becomes difficult, seek emergency medical care immediately.

Liver Damage (Hepatotoxicity)

Contact your healthcare provider immediately if you experience:

• persistent nausea or vomiting;
• abdominal pain;
• fever;
• unusual weakness or fatigue;
• itching;
• loss of appetite;
• pale stools;
• dark urine;
• yellowing of the skin or eyes (jaundice).

Heart Rhythm Changes

In rare cases, azithromycin may cause QT prolongation and torsades de pointes. Tell your doctor if you experience fainting or an irregular or fast heartbeat.

Antibiotic-Associated Diarrhea

This condition can occur even up to two months after stopping the medicine. Contact your healthcare provider if you develop watery diarrhoea, persistent diarrhoea, blood in the stool, severe stomach cramps, or fever.

Infantile Hypertrophic Pyloric Stenosis (IHPS)

In infants under six weeks old (treatment up to 42 days of life), azithromycin has been associated with reports of IHPS. Seek medical attention if your baby vomits frequently or shows signs of irritability after feeding.

Risk Factors

Several conditions may increase the risk of side effects from azithromycin.

Kidney Disease

Azithromycin is mainly eliminated through biliary excretion. In people with severe kidney impairment, clinicians may recommend closer monitoring.

Liver Disease

People with severe liver disease should use azithromycin only under a clinician's guidance and monitoring.

Heart Conditions

People with a history of heart rhythm problems or those who take other medicines that affect heart rhythm should be cautious when using azithromycin.

Drug Interactions

Azithromycin may interact with certain medicines, especially those used to treat heart conditions (for example, antiarrhythmics) and anticoagulants (blood thinners).

Managing Side Effects

• Nausea and vomiting: taking the dose with food may help many people.
• Diarrhoea: stay hydrated; seek care if it is severe, watery, or bloody.
• Stomach irritation: smaller meals may help; ask a clinician if symptoms persist.
• Skin rash or allergy symptoms: stop and seek urgent care if swelling or breathing trouble occurs.

Long-Term Use & Resistance Concerns

Azithromycin is typically used for short-term treatment of bacterial infections. Prolonged or inappropriate use can contribute to antibiotic resistance.

When to Stop Taking Azithromycin

Stop and seek medical care for severe allergic reactions, serious heart rhythm symptoms, severe diarrhoea or blood in the stool, or signs of liver injury.

Different Forms of Azithromycin

Azithromycin comes in different forms, including tablets, oral suspension, and extended-release oral suspension (Zmax). Each form has its own considerations. Below is a practical overview.

Azithromycin Tablets

Azithromycin tablets are commonly available in 250 mg and 500 mg strengths and are taken by mouth with water. This form may be prescribed for infections caused by susceptible bacteria, including certain respiratory tract infections, skin infections, and specific sexually transmitted infections (STIs) such as chlamydia.

Advantages

• Convenient dosing, often once daily (the regimen depends on the infection).
• Long half-life, which supports shorter regimens for some indications.
• Easy to store and transport: no refrigeration required.

Disadvantages

• May cause gastrointestinal side effects.
• Not suitable for people who have difficulty swallowing tablets.

Best for

• People who can swallow tablets.
• Those who prefer a simple oral dosing option.

Azithromycin Oral Suspension

Azithromycin oral suspension is a liquid form often used for children or adults who have trouble swallowing tablets. It allows flexible dosing based on weight and infection type. After reconstitution, follow the label instructions for storage and when to discard it.

Advantages

• Easier to give to people who cannot swallow tablets.
• Supports weight-based dosing in children.

Disadvantages

• Requires accurate measurement and shaking before use.
• Shorter shelf life after mixing; follow the label for discard instructions.

Best for

• Children who need weight-based dosing.
• Adults with swallowing difficulties.

Azithromycin Extended-Release Oral Suspension (Zmax)

Azithromycin extended-release oral suspension (Zmax) is a long-acting formulation typically given as a single-dose regimen for certain infections. It should be taken on an empty stomach (at least 1 hour before or 2 hours after a meal). Follow the product directions carefully.

Warnings and Precautions When Using Azithromycin

Who Should Avoid Azithromycin?

People who are allergic to azithromycin, erythromycin, or other macrolide or ketolide antibiotics should not use azithromycin. People who are allergic to any ingredient in a specific product should also avoid that product (a pharmacist can help you check the ingredient list).

Azithromycin is contraindicated in patients with a history of cholestatic jaundice or hepatic dysfunction associated with prior use of azithromycin.

Precautions Before Using Azithromycin

Use azithromycin only if a healthcare provider prescribes it, and follow the prescribed regimen.

Do not share azithromycin with others. Keep it out of the reach of children.

Important Safety Information

Hypersensitivity Reactions

Serious allergic reactions (including angioedema, anaphylaxis, and severe skin reactions) have been reported. If an allergic reaction occurs, stop the medicine and seek urgent medical care.

Hepatotoxicity

Azithromycin has been associated with liver injury. Stop taking it and seek medical care if signs of hepatitis occur.

QT Prolongation

Azithromycin can prolong the QT interval, increasing the risk of arrhythmias, especially in at-risk patients and when used with QT-prolonging medicines.

Clostridioides difficile-Associated Diarrhea (CDAD)

Seek medical care for severe, persistent, watery, or bloody diarrhoea.

Development of Drug-Resistant Bacteria

Use azithromycin only when clinically indicated.

Azithromycin Uses

Common Uses of Azithromycin

Respiratory Tract Infections

• Community-acquired pneumonia (CAP) in appropriate patients.
• Acute bacterial exacerbations of chronic bronchitis/COPD (mild to moderate).
• Pharyngitis and tonsillitis (as second-line treatment when first-line options are not appropriate).
• Acute bacterial sinusitis in selected cases.

Skin and Soft Tissue Infections

• Cellulitis (selected cases).
• Impetigo.
• Erysipelas.

Sexually Transmitted Infections (STIs)

• Uncomplicated urethritis or cervicitis due to Chlamydia trachomatis (single-dose regimens may be used in certain situations).
• Gonorrhoea: azithromycin should not be relied on as treatment.

Ear Infections (Otitis Media)

May be used in selected patients, including as an alternative when beta-lactam antibiotics are not appropriate.

Gastrointestinal Infections

• Traveller's diarrhoea: used in some cases depending on region and clinician guidance.
• Helicobacter pylori: not typically first-line in the U.S.; if used, it is part of combination treatment.

Whooping Cough (Pertussis)

In Australia, macrolides (including azithromycin) are recommended in appropriate age groups for the treatment of whooping cough and for post-exposure prophylaxis, in line with Australian immunisation guidance.

Lyme Disease (Early Stage)

May be used off-label as an alternative in some patients when first-line options are not suitable.

Prevention of Opportunistic Infections

In immunocompromised people (such as those with advanced HIV), azithromycin may be used to help prevent disseminated Mycobacterium avium complex (MAC) when clinically indicated.

Azithromycin Dosages

The dosage of azithromycin varies depending on the condition being treated, the patient's age, and the dosage form. Many regimens are taken once daily. Always follow your clinician's instructions and the product label.

Forms and Dosages of Azithromycin

• tablets (commonly 250 mg and 500 mg strengths);
• oral suspension (common concentrations include 100 mg/5 mL and 200 mg/5 mL);
• extended-release oral suspension (Zmax) (single-dose regimen for certain indications).

Azithromycin Tablets and Capsules

The typical adult dose for many bacterial infections may be 500 mg on Day 1 followed by 250 mg once daily on Days 2 through 5. In some cases, 500 mg once daily for 3 days is used. Regimens vary by diagnosis.

For children, dosing is weight-based. One common regimen is 10 mg/kg on Day 1 followed by 5 mg/kg once daily on Days 2 through 5.

Tablets should be swallowed whole with a full glass of water. Taking them with or without food is acceptable, and food may help reduce stomach discomfort.

Azithromycin Oral Suspension

The oral suspension is often used for children and for people who have difficulty swallowing tablets. Paediatric dosing is weight-based and depends on the infection being treated. Shake the suspension well before use and measure it carefully using the provided dosing device. Follow the label for storage and discard instructions after reconstitution.

Dosage Adjustments for Special Populations

No specific dose adjustment is generally required for older adults, but caution is advised in patients with QT-related risk factors and in those taking QT-prolonging medicines. In patients with liver disease, azithromycin should be used cautiously and stopped if signs of liver injury occur.

Renal impairment: no dose adjustment is generally needed for mild to moderate impairment; use caution in severe renal impairment (e.g. GFR <10 mL/min) as exposure may increase.

What to Do If You Miss a Dose

If you miss a dose of azithromycin, take it as soon as you remember. If it is close to your next scheduled dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time unless your clinician tells you to.

Overdosage of Azithromycin

Overdosage can happen if more than the prescribed amount is taken. Symptoms may include nausea, vomiting, diarrhoea, and reversible hearing impairment. Seek medical attention if an overdose is suspected. Treatment is typically supportive (for example, hydration and symptom control).

Duration of Treatment

Course length depends on the infection and the regimen prescribed. Examples include:

It is important to complete the full prescribed course, even if symptoms improve sooner, to help reduce the risk of antibiotic resistance and relapse.

Food, Drink, and Other Administration Recommendations

Azithromycin can be taken with or without food. Taking it with food may help reduce gastrointestinal discomfort for some people. Aluminium- or magnesium-containing antacids may reduce peak azithromycin levels; consider separating doses by about 2 hours unless your clinician advises otherwise.

Alcohol does not have a specific labelled interaction with azithromycin, but it may worsen stomach upset in some people.

Warnings for Specific Health Conditions

• Heart conditions - azithromycin may prolong the QT interval, increasing the risk of serious arrhythmias in at-risk patients.
• Liver disease - use cautiously and stop the medicine and seek medical care if symptoms of liver injury occur.
• Kidney disease - severe impairment (GFR <10 mL/min) may increase exposure; monitoring may be needed.
• Myasthenia gravis - azithromycin may worsen symptoms of this neuromuscular disorder.

How Quickly Should Symptoms Improve?

Some people start to feel better within a few days of starting azithromycin. If there is no improvement within a few days, symptoms worsen, or serious side effects occur, seek medical advice.

Storage

Store azithromycin tablets/capsules at room temperature: 20°C to 25°C (68°F to 77°F). Short periods between 15°C and 30°C (59°F and 86°F) are usually OK. Keep the bottle tightly closed and store it in a dry place away from heat and moisture. Do not store it in the bathroom. Keep all medicines out of reach of children.