title: Effect of 6-hourly intermittent intravenous boluses of oxmetidine and ranitidine on gastric acidity and serum prolactin.
abstract: The effect on 24-h gastric juice volume and pH of 30 min intravenous infusions of 200 and 400 mg oxmetidine and 50 mg ranitidine, administered at 6-hourly intervals, has been investigated in 12 healthy male subjects. After each infusion period a median intragastric pH greater than 5 was obtained with all active treatments, which also caused a significantly elevated 24-h median pH versus placebo. The 24-h median pH following ranitidine did not differ significantly from that after either oxmetidine treatment. There was a sharp decrease in gastric volume secretion within 2 h of infusion of each active treatment. There was no significant difference between active treatments in the time required to reach an intragastric pH greater than 5. No active treatment was able to maintain the pH greater than 5 for longer than 4 h (average 3 h). It is concluded that in patients at risk of stress ulcer, continuous infusion therapy with H2-blockers should be employed both for pharmacokinetic and practical reasons. It should be accompanied by regular measurement of pH in order to monitor any fall in pH. Alternatively, shorter time intervals than 6 h should be used for bolus therapy.
mesh_terms: D000328:Adult; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination; D006635:Histamine H2 Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D008297:Male; D011388:Prolactin / Q000097:blood*; D011897:Random Allocation; D011899:Ranitidine / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*
chemical_list: D006635:Histamine H2 Antagonists; D007093:Imidazoles; D011899:Ranitidine; D011388:Prolactin; C027703:oxmetidine