Effects of a new effervescent cimetidine formulation on gastric acidity in healthy subjects

The effect of a new effervescent formulation of 800 mg cimetidine on intragastric acidity was studied in 10 fasting healthy male volunteers. Using a randomised, cross-over design, the effect of this new cimetidine formulation was compared with that of a standard dose of a liquid aluminium/magnesium hydroxide antacid (Maalox). Intragastric pH was continuously monitored with a combination glass electrode and a digital data recorder. After a baseline period of 1 h the effect of the drugs was studied for 5 h. Both drugs increased the intragastric pH instantaneously, but the effect of Maalox ceased after 45.3 +/- 31.0 min (mean +/- SD), whereas that of effervescent cimetidine persisted for the entire 5 hr study period. Time with pH greater than 3.5, time with pH greater than 2, greater than 3, greater than 4, greater than 5 and greater than 6, and areas under the pH-time curves were significantly (P less than 0.001) higher for effervescent cimetidine than for Maalox. It is concluded that the new cimetidine formulation studied effectively combines, at least in healthy male volunteers, the immediate effect of a pH buffer with the prolonged systemic effect of an H2 blocker.