Pharmacology · Proton pump inhibitors (PPIs)
Lansoprazole !
A proton pump inhibitor for ulcers, reflux and H. pylori. Its capsule granules can be sprinkled on soft food or given through a nasogastric tube.
Updated 2026-11-01
The crystal is the pig gastric pump bound to vonoprazan, a reversible acid blocker; the figure highlights Cys813, the cysteine to which activated lansoprazole bonds covalently.
Mechanism of action
Lansoprazole is a PPI prodrug. In the acidic canaliculus of the parietal cell it becomes a reactive sulfenamide that bonds covalently to cysteines of the H⁺/K⁺-ATPase and blocks the last step of acid secretion. Basal and stimulated acid fall until the cell makes new pumps.
- Collects in the acidic canaliculus of the parietal cell
- Acid activates it into a reactive sulfenamide
- A covalent bond to Cys813 locks the H⁺/K⁺ pump
- Acid stays low until new pumps are made
Pharmacokinetics
- Absorption
- Delayed-release capsules and orally disintegrating tablets, taken before meals; capsule granules can be mixed with soft foods or apple juice.
- Metabolism
- Liver, through CYP3A and CYP2C19.
- Half-life
- Short in plasma, but the effect on the pump lasts much longer.
Indications
- Active duodenal ulcer, maintenance of healed duodenal ulcer and benign gastric ulcer. Peptic ulcer disease →
- H. pylori eradication with amoxicillin and clarithromycin (triple therapy). Helicobacter pylori gastritis →
- Healing and risk reduction of NSAID-associated gastric ulcer. Peptic ulcer disease →
- Symptomatic reflux and erosive oesophagitis, from 1 year of age. Gastro-oesophageal reflux disease (GERD) →
- Zollinger–Ellison syndrome and other hypersecretory states. Zollinger-Ellison syndrome (gastrinoma) →
Adverse effects
Common
- Diarrhoea
- Abdominal pain
- Headache
Contraindications
- Hypersensitivity to lansoprazole or other substituted benzimidazoles
- Use with rilpivirine-containing products
Key interactions
- Theophylline
- Faster theophylline clearance; its level is checked when lansoprazole is started or stopped.
- Tacrolimus
- Higher tacrolimus exposure, especially in transplant patients who metabolise CYP2C19 slowly.
- Methotrexate (mainly high doses)
- Methotrexate levels may rise and stay high longer.
- Warfarin
- INR and prothrombin time can rise; the INR is monitored.
- Drugs that need acid to be absorbed (ketoconazole, itraconazole, iron salts, atazanavir)
- Lower absorption and effect.
What is monitored
- Magnesium in long-term treatment
- INR on warfarin and levels of tacrolimus or theophylline
- Periodic review of whether it is still needed
Administration and safety
- Taken before meals
- Capsules are swallowed whole or opened and the intact granules sprinkled on a soft food such as applesauce or yoghurt; the granules are not chewed or crushed
- Through a nasogastric tube, the intact granules are mixed only with the juice and volume set in the label
- Orally disintegrating tablets dissolve on the tongue
Nursing care
- Choose the form that suits the patient: whole capsule, sprinkled granules, tube or disintegrating tablet
- Flush the nasogastric tube after giving the granules so they do not block it
- Check tacrolimus, theophylline or INR when lansoprazole is started or stopped
- Teach the patient to report watery diarrhoea or rash
Pregnancy and breastfeeding
Published observational studies overall do not show adverse pregnancy outcomes with lansoprazole; it is used when needed.
Test yourself
Think of the answer, then tap the question to see it.
How can lansoprazole be given to a patient who cannot swallow capsules?
The capsule is opened and the intact granules are sprinkled on a soft food, mixed with juice, or given through a nasogastric tube; orally disintegrating tablets also exist.
Which immunosuppressant may rise with lansoprazole, especially in slow CYP2C19 metabolisers?
Tacrolimus.
Which antibiotics are combined with lansoprazole in triple therapy for H. pylori?
Amoxicillin and clarithromycin.
Related drugs
Related conditions
- Peptic ulcer disease
- Helicobacter pylori gastritis
- Gastro-oesophageal reflux disease (GERD)
- Zollinger-Ellison syndrome (gastrinoma)
← Back to the class: Proton pump inhibitors (PPIs)
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - LANSOPRAZOLE capsule, delayed release (DailyMed (U.S. National Library of Medicine), 2026); Lansoprazole: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); RCSB PDB - 5YLU: Crystal structure of the gastric proton pump complexed with vonoprazan (RCSB Protein Data Bank, 2026).
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Representative model, for educational purposes only.