What it is
Pantoprazole inhibits the proton pump (H+/K+ ATPase) of the stomach's parietal cells. It suppresses most acid secretion and keeps gastric pH high for hours. It is more potent than H2 antagonists (such as famotidine) and allows ulcers to heal and protects the stomach of people taking NSAIDs.
What sets it apart from omeprazole is that it inhibits CYP2C19 less: it has fewer interactions, which is why it is the preferred PPI with clopidogrel. It is first line in peptic ulcer, reflux oesophagitis and gastric protection with NSAIDs or anticoagulants.
Mechanism of action
It works by inhibiting:
- The proton pump (H+/K+ ATPase) in the gastric parietal cells
- It reduces acid secretion by up to 90% at standard doses
- Maximum effect after 2–3 days (the effect builds up)
At the counter
When to recommend it
- Active peptic ulcer (stomach or duodenum)
- Reflux oesophagitis (GORD)
- Gastric protection in patients taking NSAIDs long term
- Gastric protection with oral anticoagulants
When not to
- Allergy to benzimidazoles
- Severe liver failure (dose adjustment)
- Treatment with atazanavir or rilpivirine (the PPI reduces their absorption)
- Long-term use without periodically checking whether it is still needed
Warnings
- Important Hypomagnesaemia: rare but serious with prolonged use. According to the EMA, consider monitoring magnesium in treatment lasting more than a year.
- Important Vitamin B12 malabsorption: long-term acid suppression reduces cobalamin absorption. A risk with treatment of more than 2 years.
- Caution Osteoporosis: prolonged use may increase fracture risk. Recommendation: the lowest effective dose.
- Caution CYP2C19 interactions: fewer than with other PPIs, but still present. Check other medicines.
Pharmacokinetics
- Absorption
- Rapid absorption in the small intestine (the tablet is acid-resistant). Bioavailability of 77%. Peak at 2–3 hours.
- Distribution
- It accumulates preferentially in the gastric parietal cells (its site of action). Protein binding of 98%.
- Metabolism
- Extensive hepatic metabolism via CYP2C19 and CYP3A4. It produces inactive metabolites.
- Elimination
- Renal elimination of metabolites. Half-life of about 1 hour, but the effect lasts more than 24 h because the pump stays blocked.
Pantoprazole vs H2 antagonists
| Aspect | Pantoprazole | H2 antagonist (famotidine) |
|---|---|---|
| Acid suppression | Very high | Moderate |
| Ulcer healing | Faster | Slower |
| Duration of effect | More than 24 h | 10–12 h |
| Doses a day | 1–2 | 1–2 |
| Current use | First line | Occasional alternative (ranitidine was withdrawn in 2019–2020 because of an impurity) |
Pantoprazole is better for treating and protecting. H2 antagonists remain an occasional alternative; ranitidine, the best known, is no longer marketed.
Self-assessment
Three questions. When you check your answers you will see the explanation for each one.
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Pantoprazole is a proton pump inhibitor. It blocks the pump directly in the parietal cell, not receptors.
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Although it is absorbed quickly, the maximum effect takes 2–3 days as pumps are progressively blocked. That is why improvement is gradual.
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Long-term PPI use reduces B12 absorption (acid is needed to release it from proteins). The risk applies after about 2 years and needs monitoring.
Training content. It does not replace the summary of product characteristics or clinical judgement.