Omeprazole / Lansoprazole (LPR)

How it works

It irreversibly inhibits the gastric H+/K+-ATPase (proton pump) in parietal cells, suppressing basal and stimulated gastric acid secretion.

Prescribing in practice

• Acid suppression can mask the symptoms of gastric cancer, so investigate alarm features (such as unexplained weight loss, dysphagia, gastrointestinal bleeding or persistent vomiting) before attributing symptoms to benign reflux.
• Omeprazole inhibits CYP2C19 and can reduce the activation of clopidogrel to its active metabolite, so where co-prescribing with clopidogrel is needed, choose an alternative proton pump inhibitor with less interaction.
• Long-term use is associated with hypomagnesaemia, vitamin B12 deficiency, an increased risk of fractures and Clostridioides difficile infection; review the indication periodically and deprescribe or step down where possible.

Monitoring

Reassess the continued need at each review and consider checking magnesium in prolonged therapy or where other drugs that lower magnesium are co-prescribed; consider vitamin B12 status with long-term use. Stopping abruptly after prolonged treatment can provoke rebound acid hypersecretion, so step down gradually where feasible.

Counselling the patient

• Take it before food, typically in the morning, and swallow capsules whole or open them and disperse the contents as described in the SPC if you cannot swallow them.
• Tell your doctor if you develop new or worsening difficulty swallowing, unintended weight loss, black stools or vomiting, as these need investigation.
• Do not stop a long course suddenly, as acid symptoms can temporarily return worse; discuss tapering with your prescriber.

Evidence & guidelines

Guideline-recommended for reflux and ulcer disease (NICE CG184; NICE NG12 alarm-feature referral).