Sounds like 'ra-ni-ta-dine'

Easy-to-read medicine information about ranitidine – what it is, how to take ranitidine safely and possible side effects.

Type of medicine Also called
  • Medicine to reduce stomach acid  
  • Zantac®
  • Zantac Extra®
  • Zantac Double Strength®
  • Ranitidine Relief® 
  • Peptisoothe®

What is ranitidine?

Ranitidine is used to lower high levels of acid in your stomach which can cause conditions such as indigestion, reflux, and ulcers. It can also prevent ulcers from forming, or help the healing process where damage has already occurred.

Ranitidine may also be used to prevent ulcers caused by medicines such as non-steroidal anti-inflammatory drugs (NSAIDs). Examples of NSAIDs are diclofenac, ibuprofen, naproxen.

In New Zealand, ranitidine is available as tablets (150 mg and 300 mg) and liquid, on prescription from your doctor. The tablets can also be bought from your pharmacy without a prescription for symptoms such as heartburn and indigestion.  


  • The usual dose of ranitidine is 150 mg two times a day or 300 mg once a day, at night.
  • For some people, 150 mg once a day is enough; others may need a higher dose of 600 mg a day.
  • It is best to take the lowest effective dose, for the shortest possible time.
  • Your doctor will advise you how long to take ranitidine for (usually for 4 to 8 weeks). Some people may need to take it for longer and some people may be advised to take it only as required when they have symptoms of indigestion.
  • The pharmacy label on your medicine will tell you how much ranitidine to take, how often to take it, and any special instructions.

How to take ranitidine

  • Swallow your tablets with a full glass of water.
  • Ranitidine is usually taken once a day, but some people may need to take it two times a day. Your doctor will tell you how often to take it.
  • Take ranitidine at the same times each day.
  • Ranitidine can be taken before or after food.
  • If you forget to take your dose, take it as soon as you remember. But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.

Precautions – before starting ranitidine

  • Are you pregnant, planning a pregnancy or breastfeeding?
  • Do you have problems with your kidneys?
  • Are taking any other medicines? This includes any medicines you are taking which you can buy without a prescription, as well as herbal and complementary medicines.

If so, it’s important that you tell your doctor or pharmacist before you start ranitidine. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Possible side effects

Like all medicines, ranitidine can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Stomach upset 
  • Feeling sick (nausea)
  • Bloated
  • Gas in the tummy
  • Diarrhoea
  • Constipation
  • Headache
  • Dizziness
  • Drowsiness
  • These are quite common when you first start taking ranitidine and usually goes away with time.
  • If this medicine makes you dizzy or drowsy, do not drink alcohol and do not drive.
  • Tell your doctor if these continue.
  • Worsening stomach problems, such as really bad stomach pain, blood in your stool or black stools, vomiting blood or dark-coloured vomit
  • Tell your doctor immediately or ring HealthLine 0800 611 116
  • Sign of an allergic reaction such as skin rash, itching, swelling of the lips, face, and mouth or difficulty breathing such as chest tightness, or wheezing
  • Tell your doctor immediately or ring HealthLine 0800 611 116


Ranitidine may interact with a few medications and herbal supplements, so check with your doctor or pharmacist before starting ranitidine or before starting any new medicines.

Learn more

Medsafe Consumer Information Sheet Ranitidine Relief

New Zealand Formulary Patient Information: ranitidine


  1. Ranitidine New Zealand Formulary
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 03 Jun 2019