Study Note: Pantoprazole (Proton Pump Inhibitor)

Drug Class:

Proton Pump Inhibitor (PPI)

Mechanism of Action:
Pantoprazole inhibits the H⁺/K⁺ ATPase enzyme (proton pump) located on the gastric parietal cells of the stomach. By blocking this enzyme, it reduces gastric acid secretion, thereby increasing gastric pH.

Indications (Clinical Uses):

• Gastroesophageal reflux disease (GERD)

• Peptic ulcer disease (PUD)

• Zollinger-Ellison syndrome (gastrin-secreting tumor causing hyperacidity)

• Erosive esophagitis

• Stress ulcer prophylaxis (in ICU patients)

Side Effects:

• Headache, nausea, abdominal pain, flatulence

• Long-term use may cause:

  • Vitamin B12 deficiency

  • Hypomagnesemia

  • Increased risk of fractures (due to calcium malabsorption)

  • Possible increased risk of infections such as C. difficile or pneumonia due to reduced acid defense

Drug Interactions:

• Can decrease absorption of drugs that require an acidic environment (e.g., ketoconazole, iron supplements).

• May reduce activation of clopidogrel, an antiplatelet drug, since both are metabolized by CYP2C19 enzymes.

Contraindications:

• Hypersensitivity to PPIs

• Caution in patients with liver disease or those on multiple CYP-metabolized medications.

Clinical Notes:

• Best taken before meals, preferably in the morning.

• Do not crush or chew the delayed-release tablet.

• For GERD or peptic ulcer, treatment usually lasts 4–8 weeks.

• Taper off gradually to avoid rebound acid hypersecretion.