Pharmacology · Proton pump inhibitors (PPIs)

Pantoprazole !

A proton pump inhibitor given by mouth or IV. It has fewer CYP interactions than omeprazole and does not weaken clopidogrel in studies.

Updated 2026-11-01

Class: Proton pump inhibitors (PPIs)
Transporter: Gastric H⁺/K⁺-ATPase (proton pump), α subunit
ATC code: A02BC02

Gastric H⁺/K⁺-ATPase (proton pump), α subunitPantoprazole

The crystal is the pig gastric pump bound to vonoprazan, a reversible acid blocker; the figure highlights Cys813, a cysteine to which activated pantoprazole bonds covalently.

Target in 3D: Gastric H⁺/K⁺-ATPase (proton pump), α subunit. PDB structure 5YLU (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Pantoprazole is a prodrug that collects in the acidic secretory canaliculus of the parietal cell. Acid converts it into a reactive sulfenamide that binds covalently to cysteines of the H⁺/K⁺-ATPase on the luminal side, the last step of acid secretion. Basal and stimulated acid fall whatever the stimulus, and the effect lasts beyond 24 hours because new pumps have to be made.

Collects in the acidic canaliculus of the parietal cell
Acid activates it into a reactive sulfenamide
A covalent bond to the pump's cysteines locks the H⁺/K⁺-ATPase
Acid stays low until the cell makes new pumps

Pharmacokinetics

Absorption: Enteric-coated tablets release it after the stomach; oral bioavailability is about 77% and food delays but does not reduce absorption. IV forms exist.
Distribution: About 98% bound to plasma proteins, mainly albumin.
Metabolism: Liver, mainly by CYP2C19 (demethylation, then sulfation) and partly CYP3A4.
Elimination: About 71% in the urine as metabolites and the rest in faeces; no unchanged drug in the urine.
Half-life: Short in plasma, but acid suppression lasts more than 24 hours.

Indications

Erosive oesophagitis from reflux: healing and maintenance. Gastro-oesophageal reflux disease (GERD) →
Zollinger–Ellison syndrome and other hypersecretory states. Zollinger-Ellison syndrome (gastrinoma) →
Peptic ulcer and H. pylori eradication regimens, like other PPIs. Peptic ulcer disease →
IV acid suppression in bleeding peptic ulcer is common practice, although the US label states that its efficacy for upper GI bleeding has not been established. Upper gastrointestinal bleeding →

Adverse effects

Common

Headache
Diarrhoea, nausea and abdominal pain
Flatulence
Injection-site thrombophlebitis (IV)

Contraindications

Hypersensitivity to pantoprazole or other substituted benzimidazoles
Use with rilpivirine-containing products

Key interactions

Warfarin: INR and prothrombin time can rise, with a risk of bleeding; the INR is monitored.
Drugs that need acid to be absorbed (iron salts, ketoconazole, itraconazole, erlotinib, dasatinib, mycophenolate mofetil): Less absorption and effect.
Methotrexate (mainly high doses): Methotrexate levels may rise and stay high for longer.
Clopidogrel: In healthy volunteers pantoprazole did not reduce clopidogrel's active metabolite or its platelet effect, unlike omeprazole.

What is monitored

Magnesium before and during long treatment, especially with digoxin or diuretics
Kidney function and urine if fever, rash or rising creatinine appear
Periodic review of whether it is still needed
Diarrhoea that does not improve (C. difficile)

Administration and safety

Delayed-release tablets are swallowed whole, not crushed or chewed
The IV powder is reconstituted and diluted only with the fluids listed in the label, and the line is flushed before and after
IV infusion can irritate the vein; the site is checked and the catheter removed if needed
The IV product contains edetate, which can deepen zinc deficiency in prone patients

Nursing care

Check magnesium and the list of drugs that depend on acid before long courses
Watch the IV site for redness and pain
Teach the patient to report watery diarrhoea, fever or rash
Remind the team that PPIs can cause false positive urine tests for THC and raise chromogranin A

Pregnancy and breastfeeding

Observational studies have not shown more birth defects or other adverse pregnancy outcomes; it is used when needed.

Test yourself

Think of the answer, then tap the question to see it.

Which PPI is often preferred in a patient on clopidogrel, and why?

Pantoprazole: in studies it did not reduce clopidogrel's active metabolite or its antiplatelet effect, unlike omeprazole.

Why does pantoprazole's effect last more than a day if it stays in plasma for a short time?

It binds the proton pump covalently and irreversibly; acid only recovers when the parietal cell makes new pumps.

Which antiretroviral is contraindicated with PPIs such as pantoprazole?

Rilpivirine, which needs gastric acid to be absorbed.

Which kidney adverse effect can appear at any time during PPI treatment?

Acute tubulointerstitial nephritis.

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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 - PANTOPRAZOLE SODIUM tablet, delayed release (DailyMed (U.S. National Library of Medicine), 2026); DailyMed - PANTOPRAZOLE SODIUM injection, powder, lyophilized, for solution (DailyMed (U.S. National Library of Medicine), 2026); Medications for the Treatment of Gastric Acidity - Gastroenterology - MSD Manual Professional Edition (MSD Manual Professional Edition, 2025); 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.