Kruidvat Maagzuurremmer (Omeprazole)

Omeprazole is a proton pump inhibitor used to treat acid‑related gastrointestinal disorders.

• Gastro‑oesophageal reflux disease (GERD): reduces frequency and severity of heartburn and regurgitation, and promotes healing of inflamed esophageal tissue.
• Peptic ulcer disease: accelerates ulcer closure in the stomach or duodenum by markedly lowering gastric acid output.
• Erosive esophagitis: facilitates repair of damaged esophageal lining and prevents further acid‑induced injury.
• Prevention of ulcer recurrence: maintains low gastric acidity to reduce risk of new ulcer formation in high‑risk patients.

• Omeprazole acts by irreversibly binding to the H+/K+ ATPase enzyme (the proton pump) located on the secretory surface of gastric parietal cells. This inhibition blocks the final step of acid secretion, leading to a sustained reduction in gastric hydrochloric acid output and an increase in gastric pH. The effect persists for up to 72 hours because new enzyme synthesis is required for acid production to resume.

Omeprazole may be associated with a range of adverse reactions, most of which are mild and reversible.

Common Side Effects

• Headache: mild to moderate headache reported during therapy.
• Diarrhoea: loose stools occurring especially early in treatment.
• Nausea: transient feeling of nausea or upset stomach.

Serious or Rare Side Effects

• Severe allergic reaction: rash, itching, swelling, or difficulty breathing indicating possible anaphylaxis.
• Clostridioides difficile infection: persistent diarrhoea with abdominal pain suggesting colitis.
• Low magnesium levels: hypomagnesemia causing muscle cramps, irregular heartbeat or seizures.

When prescribing omeprazole, several precautionary measures should be considered to ensure safe use.

• Assess renal and hepatic function: dose adjustment may be needed in severe impairment.
• Review concomitant medications: consider potential interactions with drugs requiring acidic pH for absorption.
• Use the lowest effective dose: limit duration to the shortest period necessary to control symptoms.
• Monitor long‑term users: watch for signs of osteoporosis, fractures, or vitamin B12 deficiency.
• Caution in pregnancy and lactation: use only if the potential benefit outweighs the risk.
• Store at ambient temperature: keep below 25 °C in the original container, protected from moisture and light.

Omeprazole can affect the pharmacokinetics of several medicines, requiring attention to avoid reduced efficacy or increased toxicity.

Major Interactions (Avoid)

• Clopidogrel: reduced antiplatelet effect leading to higher cardiovascular risk.
• Atazanavir or other protease inhibitors: decreased absorption and therapeutic failure.

Moderate Interactions (Monitor Closely)

• Warfarin: possible increase in INR, requiring closer coagulation monitoring.
• Digoxin: higher serum levels may occur, necessitating dose adjustment.
• Methotrexate: reduced renal clearance can raise toxicity risk.