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.

Ranitidine Treatment in Newborn Infants

“…No data are available in children on prolactin level changes during ranitidine therapy. Data from adult series are conflicting: while most authors were unable to find significant vari ations of basal or stimulated prolactin levels (23)(24)(25) , increased (3) as well as reduced (4) basal concentrations were reported by others. Studies in rats suggest that the drug actually inhibits prolactin release, possibly by inhibiting cerebral histamine receptors (26).…”