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Proton Pump Inhibitor — Aspiration Prophylaxis

Omeprazole (Perioperative — Aspiration Prophylaxis)

Brand names: Losec

Perioperative omeprazole is a proton pump inhibitor given before anaesthesia to raise gastric pH and reduce the severity of pulmonary injury should aspiration of gastric contents occur at induction.

Dosing — not shown for this use

The product information we hold does not support a dose for this page's specific use, route or population, so none is shown. Follow your local or national guideline, and confirm against the product SmPC.

The licensed dosing — for the medicine's licensed uses, which may differ from this page's — is on Omeprazole.

Clinical monograph

How it works

Omeprazole irreversibly inhibits the gastric H+/K+-ATPase (proton pump) of parietal cells, suppressing acid secretion and thereby reducing gastric acidity.

Prescribing in practice

  • It mitigates the consequences of aspiration but does not prevent regurgitation — it must not replace appropriate fasting, rapid-sequence induction and airway precautions in the at-risk patient.
  • Onset of acid suppression is not immediate, so timing of the preoperative dose matters and it is most useful when given in advance rather than at the moment of induction.
  • Omeprazole inhibits CYP2C19 and can reduce activation of clopidogrel; review interacting medicines around the procedure.

Monitoring

No routine monitoring is required for short perioperative use, though prolonged proton pump inhibitor therapy warrants attention to magnesium and the indication for continuation.

Counselling the patient

  • This tablet reduces stomach acid to make your anaesthetic safer.
  • Continue to follow the fasting instructions you have been given before surgery.

Evidence & guidelines

Acid-suppression prophylaxis before anaesthesia is supported by aspiration-risk guidance, with proton pump inhibitors recognised for reducing gastric acidity.

Reference: NICE NG180; OAA Obstetric Anaesthesia; ASA Aspiration Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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