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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 — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

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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