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
  • Belongs to a group of medicines called antihistamines   
  • Arrow-Ranitidine
  • Zantac
  • Ranitidine Relief® 
  • Peptisoothe®

What is ranitidine?

Ranitidine reduces the amount of acid produced in the stomach. It is used to treat a number of conditions associated with high stomach acid affecting your stomach and gut, such as indigestion, reflux, and ulcers. Ranitidine can also prevent ulcers from forming, or help the healing process where damage has already occurred. Ranitidine may 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, liquid and can be given as an injection in the hospital.  


  • The usual dose of ranitidine is 150 mg twice a day or 300 mg once a day, at night.
  • For some people, 150 mg once a day is enough.
  • The pharmacy label on your medicine will tell you how much ranitidine to take, how often to take it, and any special instructions.
  • Your doctor will advise you how long to take ranitidine for, which can range from a few days to months.

How to take ranitidine

  • Swallow your ranitidine tablet with a full glass of water.
  • 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 breast-feeding?
  • 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
  • This is quite common when you first start taking ranitidine and usually goes way with time.
  • Tell your doctor if these continue.
  • 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: Dr Janine Bycroft, GP, Health Navigator NZ