In brief
How the acid pump works and why it matters
Gastric acid is produced by parietal cells, with the final step handled by a pump enzyme that expels hydrogen ions into the stomach in exchange for potassium. Every modern acid-reducing drug targets that pump — but differently.
Proton pump inhibitors (omeprazole, pantoprazole, esomeprazole and others) are ingenious but imperfect:
▸they are prodrugs — inactive until they reach an acidic environment and convert there into the active form; ▸they bind the pump irreversibly, but only pumps that are working at that moment — hence dosing before food, when meals have activated the pumps; ▸full effect builds over several days; ▸at night, with no food, some pumps remain unblocked — hence the classic night-time breakthrough acidity.
Vonoprazan solves those four problems differently: it binds the pump directly and reversibly, competing with potassium ions. It needs no acid activation and no link to meals.
| Proton pump inhibitors | Vonoprazan | |
|---|---|---|
| Form | Prodrug, requires acid activation | Active immediately |
| Binding | Irreversible, only active pumps | Reversible, competes with potassium |
| Timing | Before food | Independent of meals |
| Onset | Several days | From the first dose |
| Night-time breakthrough | Characteristic | Less frequent |
| CYP2C19 dependence | Marked | Substantially less |
The genetics nobody mentions
PPI efficacy depends on the CYP2C19 enzyme, whose activity varies genetically between people. In rapid metabolisers the drug clears faster and suppresses acid less — an underappreciated reason why "omeprazole doesn't work for me". The proportion of such people differs markedly between populations.
Vonoprazan is metabolised differently and depends far less on that variant. Practically, this means a more predictable result without genetic testing.
What the trials showed
Reflux disease
▸A systematic review and meta-analysis (2025) compared vonoprazan with lansoprazole in erosive oesophagitis: superiority in both the healing phase and maintenance of remission, more pronounced in severe grades [1].
Helicobacter pylori
▸Phase 3 trial in the US and Europe (Gastroenterology, 2022): vonoprazan-based regimens — dual with amoxicillin and triple with amoxicillin and clarithromycin — outperformed standard PPI-based triple therapy [2]. ▸The advantage was particularly noted where the organism was clarithromycin-resistant — today's main cause of eradication failure [3].
The logic is simple: antibiotics against H. pylori work better the more stably acid is suppressed. Even suppression translates into a higher success rate.
Regimens and doses
| Situation | Regimen |
|---|---|
| Erosive oesophagitis, healing | 20 mg once daily |
| Erosive oesophagitis, maintenance | 10 mg once daily |
| Non-erosive reflux disease | 10 mg once daily |
| H. pylori, dual therapy | Vonoprazan + amoxicillin, 14 days |
| H. pylori, triple therapy | Vonoprazan + amoxicillin + clarithromycin, 14 days |
Dosing is not tied to meals — a tangible practical advantage over PPIs, which have to be remembered 30–60 minutes before breakfast.
Who actually needs it
Vonoprazan does not abolish PPIs and need not displace them. Its niche is fairly clearly drawn:
▸inadequate response to a full dose of a proton pump inhibitor; ▸severe erosive oesophagitis — where the healing advantage is most visible; ▸persistent night-time symptoms — breakthrough acidity in the small hours; ▸H. pylori eradication, especially a repeat attempt or in regions with high clarithromycin resistance.
If an ordinary PPI controls the symptoms, there is no need to change it.
Safety points to remember
▸The profile is broadly comparable to PPIs; the common complaints are gastrointestinal. ▸Stronger acid suppression predictably raises gastrin — as with PPIs, but more so. ▸The class is younger, so there is less long-term data. ▸Hence the general rule: prolonged use should be justified, not habitual. That is true of omeprazole too, but especially here.
Regimens can be discussed at a consultation; the product can be ordered here.
References
1. Ali SH, et al. Vonoprazan versus lansoprazole in the healing and maintenance phase of erosive esophagitis: a systematic review and meta-analysis. Dig Dis Sci. 2025. PMID 40742526
2. Chey WD, et al. Vonoprazan triple and dual therapy for Helicobacter pylori infection in the United States and Europe: randomized clinical trial. Gastroenterology. 2022;163(3):608–623. PMID 35679950
3. Malfertheiner P, et al. Potassium-competitive acid blocker and proton pump inhibitor-based regimens for first-line Helicobacter pylori eradication. Gastro Hep Adv. 2022. PMID 39131848
4. VOQUEZNA (vonoprazan) US Prescribing Information, Phathom Pharmaceuticals.
Key facts
- Vonoprazan (brand name Voquezna, Phathom Pharmaceuticals) is a potassium-competitive acid blocker (P-CAB), not a proton pump inhibitor. The class differs even though the target — the parietal cell proton pump — is the same.
- Proton pump inhibitors (omeprazole, pantoprazole and others) are prodrugs: they need an acidic environment to convert into the active form, and they bind only pumps that are currently active. Hence the requirement to take them before food and the gradual build-up of effect over several days.
- Vonoprazan binds the pump directly and reversibly, competing with potassium ions. It requires no activation, works from the first dose and is independent of meals.
- The practical consequence is more stable acid suppression across 24 hours, including at night, when breakthrough acidity on PPI therapy is most common.
- Another difference is metabolism. PPI efficacy depends on the genetic variant of the CYP2C19 enzyme: in rapid metabolisers the drug works less well. Vonoprazan shows substantially less of this dependence.
- In erosive oesophagitis, vonoprazan outperformed lansoprazole in both healing and maintenance of remission, particularly in severe grades (systematic review and meta-analysis, 2025).
- For Helicobacter pylori, vonoprazan-based regimens beat standard PPI-based triple therapy in a phase 3 trial conducted in the United States and Europe (Gastroenterology, 2022).
- Core regimens: for GERD — 20 mg daily to heal erosive oesophagitis and 10 mg daily for maintenance; for H. pylori — dual therapy (with amoxicillin) or triple therapy (with amoxicillin and clarithromycin) for 14 days.
- The safety profile is broadly comparable to PPIs. Stronger acid suppression predictably raises gastrin more, so long-term use requires justification, exactly as with PPIs.
- There is no reason to switch a working PPI to vonoprazan for its own sake. The niche is inadequate PPI response, severe erosive oesophagitis, persistent night-time symptoms, and H. pylori eradication in regions with high clarithromycin resistance.
