Omeprazole

Omeprazole was the first proton pump inhibitor to reach the market and remains one of the most prescribed medications globally. It suppresses gastric acid production by irreversibly inhibiting the hydrogen-potassium ATPase enzyme system in gastric parietal cells, providing effective relief from acid-related conditions.

Omeprazole is used to treat GORD, peptic ulcers, Zollinger-Ellison syndrome, and as part of H. pylori eradication therapy. It is available in capsule form and as a dispersible tablet for those who have difficulty swallowing.

How to Take Omeprazole

Take one capsule daily, 20 to 30 minutes before breakfast. Swallow it whole and do not crush or chew. Omeprazole works best when taken before eating, because the acid-producing cells in the stomach are most active when triggered by food.

For H. pylori eradication, omeprazole is taken twice daily alongside two antibiotics for seven to fourteen days. Always complete the full course even if you start feeling better sooner. For long-term use, your doctor should review whether the lowest effective dose is being used.

For GORD: 20 mg once daily for four to eight weeks. For peptic ulcer: 20 mg to 40 mg once daily for four to eight weeks. Maintenance: 10 mg to 20 mg daily. For H. pylori eradication: 20 mg twice daily as part of triple therapy.

Common Side Effects

Common side effects include:

• Headache
• Nausea
• Diarrhoea or constipation
• Abdominal pain
• Wind

These are generally mild and temporary. With long-term use, omeprazole can slightly increase the risk of bone fractures, vitamin B12 deficiency, and low magnesium. Discuss ongoing use with your doctor and make sure you are getting enough calcium and vitamin D.

Alarm symptoms (unintentional weight loss, dysphagia, vomiting blood, melaena) require urgent investigation before or during PPI therapy. Omeprazole interacts with clopidogrel and may reduce its antiplatelet effect; an alternative PPI may be preferred in patients taking clopidogrel.

Contraindicated in known hypersensitivity to omeprazole or other PPIs. Should not be used with atazanavir or nelfinavir.