Medicines & Supplements A to Z > Azithromycin


Last updated on 18/03/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Azithromycin


BRAND NAME(S) IN HONG KONG: Sumamed, Zithromax

DRUG CLASS: Macrolide antibiotic

USED FOR: Bacterial infections

OTHER DRUGS IN THE SAME CLASS: Clarithromycin, Erythromycin, Roxithromycin

– 250mg, 500mg (tablets)
– 500mg (injections)
– 200mg/5ml (oral suspension)

What is Azithromycin for?

Azithromycin is a macrolide antibiotic, and is used for treating bacterial infections, including but not limited to the following: 

– Respiratory tract infections
– Otitis media (ear infections)
– Skin and soft tissue infections
– Community-acquired pneumonia
– Uncomplicated genital chlamydial infections
– Gonorrhea
– Pertussis (whooping cough)

How to use it?

For respiratory-tract infections / otitis media /  skin and soft-tissue infections


500 mg once daily for 3 days OR initially 500 mg once daily for 1 day, then 250 mg once daily for 4 days.

Child 6 months–17 years
10 mg/kg once daily (max. per dose 500 mg) for 3 days.

Child 6 months–17 years (body-weight 15–25 kg)
200 mg once daily for 3 days.

Child 6 months–17 years (body-weight 26–35 kg)
300 mg once daily for 3 days.

Child 6 months–17 years (body-weight 36–45 kg)
400 mg once daily for 3 days.

Child 6 months–17 years (body-weight 46 kg and above)
500 mg once daily for 3 days.

For community-acquired pneumonia 


500 mg once daily for 3 days OR initially 500 mg once daily for 1 day, then 250 mg once daily for 4 days.

For uncomplicated genital chlamydial infections


Adult / Child 12-17 years
1 g for 1 dose

For uncomplicated gonorrhea


1 g for 1 dose.

For pertussis 


500 mg as a single dose on day 1, then 250 mg daily on day 2-5; Total course of therapy: 7 days.

Child 6 months or below
10 mg/kg/day as a single dose for 5 days.

Child 6 months or above
10 mg/kg as a single dose on day 1 (up to a maximum of 500 mg), then 5 mg/kg/day on day 2-5 (up to a maximum of 250 mg).

What are the side effects of Azithromycin?

Common side effects of Azithromycin include decreased appetite, diarrhoea, gastrointestinal discomfort,  nausea, and vomiting.

Who should not take Azithromycin?

Anyone who has an allergy to Azithromycin or another macrolide antibiotic.

Pharmacist Tips:

Common dosing schedule:
Can be taken with or without food.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Azithromycin may interact:
– Ergotamine
– QT-prolonging medicines, e.g. antiarrhythmics, antipsychotics

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Azithromycin in Hong Kong?

In Hong Kong, Azithromycin is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Azithromycin in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor. 

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.