title: [The effect of preoperative oral administration of ranitidine on pH and volume of gastric juice].
abstract: The effect of ranitidine, administrated 2 or 4 hours prior to induction of anesthesia, on volume and pH of gastric juice was investigated in patients undergoing elective surgery. Three-hundred mg of ranitidine was administrated orally in 54 patients 2 hours prior to anesthesia and in 50 patients 4 hours prior to anesthesia. The volume and pH of gastric juice were measured immediately after induction of anesthesia. In more than 90% of patients of both groups, volume of gastric juice was smaller than 25 ml and its pH was more than 2.5. Ranitidine 450 mg was administrated orally in 7 patients, and its plasma concentration was measured 2, 4 and 6 hours after administration. In one patient, volume of gastric juice was larger than 25 ml and its pH was less than 2.5. Ranitidine concentration in this patient was below the effective level 2 hours after administration and it was above the level after 4 hours. We concluded that oral administration of ranitidine 300 mg, 4 hours preoperatively, could be more effective to prevent aspiration pneumonitis than when it is given 2 hours preoperatively.
authors.affiliation: Department of Anesthesiology, Sendai Red Cross Hospital.
authors.forename: K
authors.initials: K
authors.lastname: Momose
authors.forename: T
authors.initials: T
authors.lastname: Shima
authors.forename: S
authors.initials: S
authors.lastname: Haga
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: Y
authors.initials: Y
authors.lastname: Koga
authors.forename: Y
authors.initials: Y
authors.lastname: Hashimoto
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D005260:Female; D005750:Gastric Juice / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D011015:Pneumonia, Aspiration / Q000517:prevention & control; D011300:Preoperative Care; D011899:Ranitidine / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D011899:Ranitidine