Vonoprazan
P-CABs
Potassium-competitive acid blockers (P-CABs)
A potassium-competitive acid blocker that switches off the stomach's proton pump quickly. Used for erosive oesophagitis, heartburn and H. pylori.
Quick facts
- Group
- Potassium-competitive acid blockers (P-CABs)
- Target
- Gastric H+/K+-ATPase (proton pump), potassium-binding site
- Used for
- Healing and maintenance
- Key effects
- Diarrhoea · Bloating · Nausea
- Monitor
- Symptom relief and healing · Magnesium and vitamin B12
- ATC
- A02BC08
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows vonoprazan in the pig gastric proton pump, which is very similar to the human pump.
Vonoprazan is a pyrrole-based weak base that accumulates in the acid space of parietal cells and binds reversibly to the potassium-binding site of the H+/K+-ATPase. It blocks the final step of acid secretion without needing activation by acid, so it acts fast and keeps acid low, including at night. Less acid heals the oesophagus and helps antibiotics work against H. pylori.
- Vonoprazan concentrates in the parietal cell
- It blocks the pump's potassium site, reversibly
- Acid secretion stops; oesophagus heals
Indications
- Healing and maintenance of erosive oesophagitis; heartburn of reflux disease Gastro-oesophageal reflux disease (GERD) →
- Helicobacter pylori eradication, with amoxicillin with or without clarithromycin Helicobacter pylori gastritis →
Adverse effects
Common
- Diarrhoea
- Bloating, abdominal pain
- Nausea, indigestion
- Headache, cold symptoms
Contraindications
- Hypersensitivity to vonoprazan or any component
Key interactions
- Iron supplements and other drugs that need acid for absorption
- Less absorption when stomach acid is low
- St John's wort and other CYP3A4 inducers
- Lower vonoprazan levels
- Clarithromycin (in H. pylori packs)
- Clarithromycin brings its own CYP3A4 interactions; the whole medication list is checked
What is monitored
- Symptom relief and healing
- Magnesium and vitamin B12 with long-term use
- Diarrhoea, kidney function, bone health
Administration and safety
- Oral tablet, with or without food; swallowed whole, not split, chewed or crushed.
- Also supplied in co-packs with antibiotics for H. pylori; the whole course is completed.
- Look-alike with -prazole PPIs: vonoprazan is a different class.
Pregnancy and breastfeeding
Human data are limited; use in pregnancy needs a clear benefit and a discussion with the prescriber.
Nursing care
- Ask about kidney or liver disease, osteoporosis and low B12 or magnesium.
- Review all medicines, including iron and herbal products.
- Teach to report persistent watery diarrhoea, fever, rash, little urine or muscle cramps.
- For H. pylori, stress taking every antibiotic dose to the end.
Pharmacokinetics
- Metabolism
- Mainly hepatic CYP3A4; depends less on CYP2C19 than PPIs
Test yourself
Think of the answer, then tap the question to see it.
Where on the proton pump does vonoprazan bind?
At the potassium-binding site, reversibly and competitively.
Does vonoprazan need acid activation like omeprazole?
No; it is not a prodrug.
Which two antibiotics are combined with it for H. pylori?
Amoxicillin and clarithromycin.
Connections
← Back to the class: Potassium-competitive acid blockers (P-CABs)
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Vonoprazan: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); RCSB PDB - 5YLU: Crystal structure of the gastric proton pump complexed with vonoprazan (RCSB Protein Data Bank, 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.