Meta-analysis: comparative efficacy of H2-receptor antagonists and proton pump inhibitors for reducing aspiration risk during anaesthesia depending on the administration route and schedule.

H2-receptor antagonists (H2RA) and proton pump inhibitors (PPI) are widely used for aspiration prophylaxis in patients receiving general anaesthesia. Many randomized trials have compared these agents but it remains unclear which drug type is more effective in reducing the number of patients at risk of complications. The study aimed to compare their efficacy for decreasing the number of patients at risk of acid aspiration during general anaesthesia. Major databases were systematically searched. Randomized controlled trials comparing PPI and H2RA were selected. Sub-analyses were performed considering the dose, the dosing schedule, and the route of administration. Eighteen studies fulfilled the inclusion criteria. The main analysis showed a non-significant trend for H2RA being more effective than PPI. Only when both drugs were administered per os, as a single dose and immediately before surgery, was H2RA significantly more effective than PPI. By contrast, the effect of PPI and H2RA was similar when they were administered in two doses (the night before and on the morning of surgery) or when the drugs were given intravenously. A single H2RA dose before surgery is highly effective in reducing the number of patients at risk of acid aspiration. PPI administered in two oral doses or in a single intravenous infusion seems to be as effective as H2RA.