EFFECTS ON GASTRIC ACID SECRETION: MISOPROSTOL, OVER THE RANGE OF 50-200 MCG, INHIBITS BASAL AND NOCTURNAL GASTRIC ACID SECRETION, AND ACID SECRETION IN RESPONSE TO A VARIETY OF STIMULI, INCLUDING MEALS, HISTAMINE, PENTAGASTRIN, AND COFFEE. ACTIVITY IS APPARENT 30 MINUTES AFTER ORAL ADMINISTRATION AND PERSISTS FOR AT LEAST 3 HOURSUTERINE EFFECTS : MISOPROSTOL HAS BEEN SHOWN TO PRODUCE UTERINE CONTRACTIONS THAT MAY ENDANGER PREGNANCY.