Lansoprazole

Lansoprazole is a proton pump inhibitor (PPI) used to reduce the production of stomach acid.

It is prescribed for the treatment and prevention of gastro-oesophageal reflux disease (GORD), gastric and duodenal ulcers, Zollinger-Ellison syndrome, and as part of Helicobacter pylori eradication regimens in combination with antibiotics.

The drug works by irreversibly blocking the hydrogen-potassium adenosine triphosphatase enzyme system (the proton pump) on the surface of gastric parietal cells.

This is the final step of acid production, so lansoprazole effectively suppresses both basal and stimulated gastric acid secretion.

A single daily dose can reduce stomach acid output by approximately 80% to 90%.

Lansoprazole is well absorbed orally, and its acid-suppressing effect typically begins within one to two hours of administration.

Although the plasma half-life is relatively short, the duration of acid suppression extends beyond 24 hours owing to the irreversible nature of enzyme inhibition.

New proton pumps must be synthesised before acid secretion returns to baseline levels.

Take lansoprazole capsules in the morning, 30 minutes before breakfast, for best effect.

Swallow the capsule whole with a glass of water; do not crush or chew it, as the granules inside are enteric-coated to prevent degradation by stomach acid.

If you have difficulty swallowing capsules, they may be opened and the granules mixed with a small amount of soft food or apple juice and swallowed immediately without chewing.

For gastro-oesophageal reflux disease: 15 mg to 30 mg once daily for 4 to 8 weeks. For duodenal ulcer healing: 30 mg once daily for 2 to 4 weeks.

For gastric ulcer healing: 30 mg once daily for 4 to 8 weeks. For H. pylori eradication: 30 mg twice daily in combination with two antibiotics for 7 days.

Maintenance therapy, where indicated, is typically 15 mg once daily.

Common (1 in 10 to 1 in 100): headache, diarrhoea, nausea, abdominal pain, flatulence, constipation. Uncommon (1 in 100 to 1 in 1,000): dizziness, dry mouth, fatigue, arthralgia, rash.

Rare (1 in 1,000 to 1 in 10,000): microscopic colitis, hypomagnesaemia, interstitial nephritis. Very rare (less than 1 in 10,000): severe skin reactions, hepatitis, blood dyscrasias, pancreatitis.

Prolonged use may be associated with increased risk of bone fractures and Clostridium difficile infection.

Long-term PPI use should be reviewed regularly, as prolonged treatment has been associated with hypomagnesaemia, vitamin B12 deficiency, increased risk of hip and spine fractures, and Clostridium difficile-associated diarrhoea.

Lansoprazole may mask symptoms of gastric malignancy, and serious pathology should be excluded before commencing treatment, particularly in patients with alarm features such as unintentional weight loss, dysphagia, or gastrointestinal bleeding.

Rebound acid hypersecretion may occur when stopping treatment abruptly after prolonged use.

Do not take lansoprazole if you are allergic to the active substance or to any of its excipients.

It should not be co-administered with atazanavir, as lansoprazole significantly reduces plasma levels of this antiretroviral.

Caution is advised in patients with severe hepatic impairment, where dose reduction may be necessary.