NZ Formulary



What does it do?

Omeprazole is used to treat and prevent some stomach and gut problems, such as indigestion, reflux, and ulcers. It reduces the amount of acid made in your stomach.

Before you start

  • Tell your health professional if you are pregnant, planning to become pregnant, or breastfeeding.

How should you take it?

Take omeprazole regularly as directed with a glass of water. You can take it with or without food, but it may work better if you take it before food.
Capsules or tablets: If you have trouble swallowing you can open the capsule or break the tablet and mix with a small amount of soft food or liquid. Swallow without chewing. Do not crush the capsule contents or tablets.
Liquid: Shake well before use. Measure each dose carefully with an oral syringe or measuring spoon.

What if you forget a dose?

If it is nearly time for your next dose, skip the missed dose and take your next dose at the usual time. Otherwise, take the missed dose as soon as you remember. Do not take two doses at the same time.

Can you take other medicines?

Some medicines available without a prescription may react with omeprazole including:

  • iron supplements (e.g. Ferro-Tab®)

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products (e.g. St John's wort) or recreational drugs.

Important information continues on next page.

What side effects might you notice?

Side EffectsRecommended action

Muscle twitching or cramps, tiredness or weakness, tingling or numbness (may be signs of low magnesium)

Tell your doctor


Stomach upset

Tell your health professional if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • If your symptoms are well managed, your doctor may recommend stopping omeprazole. When you stop you may get symptoms like reflux and heartburn but these should only last for a few weeks. Talk to your health professional if these are troublesome, or if they do not get better.
  • Long-term use of omeprazole may cause side effects such as weak bones and gut infections. Tell your doctor if you develop severe or persistent diarrhoea and abdominal pain.
  • Store omeprazole liquid in the fridge. If you have any liquid leftover after the expiry date on the bottle, take it back to your pharmacy.