Dose-response study of oral famotidine for reduction of gastric acidity and volume in outpatients and inpatients.

A relatively new H2-antagonist, famotidine, has become clinically available, but its effectiveness in decreasing gastric acidity and volume has not been compared in inpatients and outpatients. We reexamined the difference in gastric acidity and volume in inpatients and outpatients, and tested the effectiveness of different oral doses and dosage regimens of famotidine in reducing gastric acidity and volume in both groups of patients. Patients received either placebo or 20 mg or 40 mg of famotidine orally the night before surgery (HS) and on the morning of surgery (AM). One hundred forty-two inpatients and 180 outpatients were randomized to one of seven groups as follows: 1) placebo (HS)/placebo (AM); 2) 20 mg of famotidine (HS)/20 mg of famotidine (AM); 3) 20 mg of famotidine (HS)/placebo (AM); 4) placebo (HS)/20 mg of famotidine (AM); 5) 40 mg of famotidine (HS)/40 mg of famotidine (AM); 6) 40 mg of famotidine (HS)/placebo (AM); and 7) placebo (HS)/40 mg of famotidine (AM). We measured the gastric acidity and volume after induction of anesthesia and found no difference between the inpatients and outpatients, with or without famotidine. We found that famotidine given HS and AM or AM only was effective in reducing gastric acidity in both groups of patients, and that there was no difference between the 20-mg and 40-mg doses of famotidine. Gastric volume was not affected by any famotidine dose.