Coming soon: AboutKidsHealth is getting a new look! Learn more Watch a video tour


Your child needs to take the medicine called omeprazole (say: o-MEP-ra-zole). This information sheet explains what omeprazole does, how to give it, and what side effects or problems your child may have when he or she takes this medicine.

What is omeprazole?

Omeprazole is a medicine that helps the stomach make less acid. It is used to treat patients with reflux disease, inflammation of the throat or stomach lining, or bleeding in the stomach. It may also be used with antibiotics to treat ulcers. You may hear omeprazole called by its brand name, Losec®. Omeprazole comes as tablets, capsules, or liquid.

Before giving omeprazole to your child

Tell your doctor or pharmacist if your child is allergic to omeprazole.

Talk with your doctor or pharmacist if your child has any of the following conditions. Precautions may need to be taken with this medicine if your child has:

  • liver disease: this condition may cause omeprazole to build up in the body

How should you give your child omeprazole?

Give this medicine exactly as your doctor or pharmacist tells you, even if your child seems better.

  • Give this medicine half an hour before food.
  • Try to give this medicine at the same time each day.
  • Give the whole tablet or capsule to your child, with water or juice.

If your child is taking liquid omeprazole, follow these instructions:

  • Shake the liquid omeprazole very well before giving each dose.
  • Measure the dose with the special spoon or syringe that the pharmacist gave you.
  • Place the bottle of omeprazole back in the refrigerator immediately after drawing up your child's dose.
  • If you are giving liquid omeprazole to your child through a g-tube or NG-tube, be sure to flush the tube very well with water immediately after giving your child the dose.
  • Do not mix the omeprazole liquid in any food or drink (other than water) before giving to your child. Mixing omeprazole in something other than water may cause the omeprazole not to work.

If you are using the tablet form and your child cannot swallow the whole tablet or needs only part of a tablet, follow these steps:

  • Let it soak in a bit of water in a medication cup until it is a little softened.
  • Peel the coating off (it will now look like a piece of plastic).
  • Throw the coating away.
  • Let the rest of the tablet disperse (spread out) in the water.
  • Mix it up well.
  • Give the medication to your child.

When do you need to give your child an antacid with omeprazole?

  • If you give your child a crushed or broken tablet in water by mouth, you need to give your child an antacid, so that the omeprazole works properly. If you give your child a tablet by G-tube or NG-tube, you also need to give your child an antacid. 
  • Omeprazole works best when there is no acid. The stomach has acid. The pink coating on the omeprazole tablet helps protect it from the stomach acid. If the tablet is broken or the coating is peeled off, this protection is gone.
  • An antacid helps protect the omeprazole tablet from acid when the pink coating is removed.

Give the antacid 20 to 30 minutes before each dose of omeprazole. Use an antacid such as Maalox® or Diovol®. You may buy the antacid at any pharmacy.

Children less than 2 years old Give 2.5 to 5 mL
Children 2 to 12 years old Give 5 to 15 mL
Children older than 12 years old Give 15 to 30 mL

You should give the antacid for the first week that your child is taking omeprazole, unless your doctor tells you not to. Your doctor will tell you how long to use the antacid.

  • If your child has kidney problems, your doctor or pharmacist may tell you not to give your child the antacid.
  • If you give your child a crushed or broken tablet in water by J-tube or NJ-tube, you do not need to give an antacid.

What should you do if your child misses a dose of omeprazole?

  • Give the missed dose as soon as you remember.
  • If it is almost time for the next dose, skip the missed dose. Give the next dose at the regular time.
  • Do not give your child two doses to make up for one missed dose.

How long does omeprazole take to work?

It may take several days for this medicine to help your child feel better. It may take up to 1 month for the medicine to have full effect.

What are the possible side effects of omeprazole?

Your child may have some of these side effects while he or she takes omeprazole. Check with your child’s doctor if your child continues to have any of these side effects, and they do not go away, or they bother your child:

  • watery bowel movements (diarrhea)
  • stomach ache
  • gas, upset stomach, or throwing up
  • headache
  • unusual drowsiness, tiredness
  • rash
  • trouble having a bowel movement (constipation)

Most of the following side effects are not common, but they may be a sign of a serious problem. Call your child’s doctor right away or take your child to the Emergency Department if your child has any of these side effects:

  • a lasting sore throat​ or hoarseness
  • yellow eyes or skin
  • frequent need to pass urine
  • bloody or cloudy urine
  • pain or difficulty passing urine
  • chest pain

What safety measures should you take when your child is using omeprazole?

There are some medicines that should not be taken together with omeprazole or in some cases the dose of omeprazole or the other medicine may need to be adjusted. Make sure that your doctor or pharmacist knows if your child is also taking:

Check with your child’s doctor or pharmacist before giving your child any other medicines (prescription, non-prescription, herbal, or natural products).

Keep a list of all medications your child is on to show the doctor or pharmacist.

What other important information should you know about omeprazole?

Your doctor may ask you to give an antacid to your child before each dose of omeprazole. The doctor may tell you to use the antacid for the first week that your child gets omeprazole. Do not give your child an antacid without speaking to your doctor or pharmacist first.

Make sure you always have enough omeprazole to last through weekends, holidays, and vacations. Call your pharmacy at least 2 days before your child runs out of medicine to order refills.

Omeprazole liquid must be made by a pharmacy. Make sure your pharmacy is able to make it for your child.

Keep omeprazole tablets and capsules at room temperature in a cool, dry place away from sunlight. Do not store it in the bathroom or kitchen.

Keep omeprazole liquid in a refrigerator. It is important that you return the bottle to the refrigerator immediately after each use. If you leave it out of the fridge for more than 24 hours, then do the following:

  • If the room was very hot (greater than 30 to 35ºC), replace it as soon as you can. You could use the liquid for one more dose as long as the liquid has not turned brown.
  • If the room was cool (23 to 25ºC), then you can use the liquid for another 24 hours as long as the liquid has not turned brown. Get it replaced within the 24-hour period.

Omeprazole liquid should not be used if it has turned brown.

Omeprazole liquid is a grainy liquid and you will see that it settles down at the bottom of the bottle. You need to shake your bottle very well before drawing up the dose in the syringe.

Do not share your child’s medicine with others. Do not give anyone else’s medicine to your child.

Do not keep any medicines that are out of date. Check with your pharmacist about the best way to throw away outdated or leftover medicines.

Keep omeprazole out of your child’s sight and reach and locked up in a safe place. If your child takes too much omeprazole, call the Ontario Poison Centre at one of these numbers. These calls are free.

  • Call 416-813-5900 if you live in Toronto.
  • Call 1-800-268-9017 if you live somewhere else in Ontario.
  • If you live outside of Ontario, call your local Poison Information Centre.

Disclaimer: The information in this Family Med-aid is accurate at the time of printing. It provides a summary of information about omeprazole and does not contain all possible information about this medicine. Not all side effects are listed. If you have any questions or want more information about omeprazole, speak to your health care provider.

Jennifer Drynan-Arsenault, BSc, RPh, ACPR