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Omeprazole

Chinese name:

奧美拉唑

Reviewed by

Joseph Blais, Pharmacist

Expert Advisory Board Member

Last Updated: 2022-05-03

What is Omeprazole for?

Omeprazole is a proton pump inhibitor which suppresses the production of stomach acid by stopping the proton pump from working. It is therefore used for a wide variety of gastrointestinal disorders including the following:

Helicobacter pylori eradication (in combination with antibiotics)
Benign gastric ulcer
Gastric ulcer
Duodenal ulcer
Prevention of NSAID-associated gastric ulcer / duodenal ulcer in patients with an increased risk of gastroduodenal complications who require continued NSAID treatment
Gastroesophageal reflux disease (GERD)
Zollinger-Ellison syndrome

How to use it?

The adult oral doses for different uses are listed below:

For H pylori eradication (in combination with antibiotics)
20 mg twice daily.

For treatment and prevention of benign gastric ulcer
20 mg once daily for 8 weeks, increase the dose in severe or recurrent cases to 40 mg once daily.

For treatment and prevention of duodenal ulcer
20 mg once daily for 4 weeks, increase the dose in severe or recurrent cases to 40 mg once daily.

For prevention of relapse in gastric ulcer
20 mg once daily, increase the dose if necessary to 40 mg once daily.

For prevention of relapse in duodenal ulcer
20 mg once daily, increase the dose if necessary to 10-40 mg daily.

For treatment and prevention of NSAID-associated duodenal ulcer / gastric ulcer / gastroduodenal erosions
20 mg once daily for 4 weeks, continue the treatment for 4 more weeks if complete healing is not achieved.

For prevention in patients in with a history of NSAID-associated duodenal ulcer / gastric ulcer / gastroduodenal lesions / dyspeptic symptoms who require continued NSAID treatment
20 mg once daily.

For Zollinger–Ellison syndrome
Start with 60 mg once daily, the usual dose is 20-120 mg daily. For the dose that is greater than 80 mg per daily, Omeprazole should be taken in 2 divided doses.

For treatment and prevention of gastroesophageal reflux disease
20 mg once daily for 4 weeks, continue the treatment for 4-8 more weeks if complete healing is not achieved. Maintenance dose is 20 mg once daily.

For gastroesophageal reflux disease that does not respond to other treatments
40 mg once daily for 8 weeks. Maintenance dose is 20 mg once daily.

As a long-term treatment for acid reflux disease
10 mg once daily. If symptoms recur, increase the dose to 20 mg once daily.

For dyspepsia (heartburn)
10-20 mg once daily for 2-4 weeks according to responses.

What are the side effects of Omeprazole?

Common side effects of Omeprazole include constipation, diarrhoea, dizziness and headache. Long-term use of proton pump inhibitors can lead to Magnesium deficiency.

Who should not take Omeprazole?

Anyone who has an allergy to Omeprazole or any component of the product.

Pharmacist Tips:

There is a risk of developing magnesium deficiency when taking Omeprazole. Magnesium deficiency can cause symptoms such as muscle spasms, tremors and loss of appetite. Magnesium supplementation can be taken if Magnesium deficiency occurs.
Omeprazole tablets should be swallowed whole. Do not split, crush, or chew.

Common dosing schedule:

Omeprazole may be taken with or without food.
If you mostly have nighttime symptoms while lying in the bed, take this medication in the evening.
If you mostly have symptoms during the daytime with stress or meals, take this medication in the morning.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Omeprazole may interact with:

Some medicines for cancer, such as EGFR inhibitors (e.g. Erlotinib, Gefitinib)
Some antifungals, e.g. Itraconazole, Ketoconazole, Posaconazole
HIV medications, e.g. Rilpivirine
Certain antibiotics, e.g. Rifampicin

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Omeprazole in Hong Kong?

In Hong Kong, Omeprazole can be purchased without a prescription from a pharmacy in Hong Kong by speaking with a pharmacist. 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 https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Omeprazole 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.

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