A double-blind randomized study was conducted in 37 patients undergoing elective abdominal surgery (excluding gastric operations) who were given either oral ranitidine 300 mg or placebo at 10 p. m. in the evening before the day of surgery. The mean interval between premedication and induction of anesthesia was 12 hours.

Findings of the study -

• Ranitidine was associated with a significant reduction (P<0.05) in the amount of gastric juice, in comparison with placebo.
• None of the patients who received ranitidine had an increased risk of acid pulmonary aspiration (pH < 2.5 and volume > 25 ml).
• Four patients in the control group were found to have an increased risk of acid pulmonary aspiration (21%).
• Mean ranitidine blood level was 237 ng/ml at the time of induction of anesthesia.

In elective abdominal surgery, ranitidine premedication was associated with a reduction in the risk for acid pulmonary aspiration.

Source: Aromaa U, Kalima TV. Ranitidine and prevention of pulmonary aspiration syndrome. Acta Anaesthesiol Scand. 1986;30:10-12.