Medicines & Supplements A to Z > Ranitidine


Last updated on July 3, 2019.

Overview   |   Dosage   |   Side Effects   |   Where To Buy  

GENERIC NAME: Ranitidine 


COMMON BRANDS IN HONG KONG: Zantac 善胃得, Ulticer 

What is Ranitidine for?

Ranitidine belongs to a class of medications called histamine-2 receptor blockers. It works by suppressing the secretion of stomach acid and can be used to treat several gastrointestinal disorders, including benign gastric and duodenal ulceration, gastroesophageal reflux disease (GERD), dyspepsia (indigestion), erosive oesophagitis, and NSAID-associated ulceration. 

How to use it?

Ranitidine can be taken by mouth as tablets or syrup and by injections. The oral doses for different uses and age groups are listed below (the dose shown is an adult dose unless specified): 

For benign gastric and duodenal ulceration 


150 mg twice daily for 4-8 weeks OR 300 mg once daily at night for 4-8 weeks. 

Child 1-5 months 

1mg/kg 3 times daily. The maximum dose is 3mg/kg 3 times daily. 

Child 6 months – 2 years

2-4 mg/kg twice daily. 

Child 3 – 11 years 

2-4 mg/kg twice daily. The maximum dose is 150 mg. 

Child 12-17 years 

150 mg twice daily OR 300 mg once daily at night. 


150 mg twice daily OR 300 mg once daily at night for up to 8-12 weeks if necessary. For moderate to severe cases, 600 mg daily in 2-4 divided doses for up to 12 weeks. 

For dyspepsia and heartburn

For short-term dyspepsia, you should take 75 mg and may repeat up to 4 doses if necessary (a maximum of 300 mg per day). 

For chronic episodic dyspepsia, you should take 150 mg twice daily for up to 6 weeks.

What are the side effects of Ranitidine? 

Common side effects of Ranitidine include diarrhoea, fatigue, and headache.

Where to buy Ranitidine in Hong Kong?

In Hong Kong, Ranitidine is an over-the-counter medicine and can be purchased without a prescription from any retail outlet in Hong Kong. This includes grocery stores, convenience stores, medicine shops, and pharmacies. 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

For detailed information about the use of Ranitidine 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.