Prevention of the acetylsalicylic acid-induced changes of the gastric potential difference by the new synthetic prostaglandin E1 analogue rioprostil.

The protective effect of 50 and 100 micrograms of the synthetic prostaglandin E1 analogue rioprostil (2-decarboxy-2-hydroxymethyl-15-deoxy-16RS-hydroxy-16-methyl PGE1) against the 0.5 and 1 g acetylsalicylic acid (ASA)-induced changes of gastric potential difference (PD) was compared to that of placebo in a double-blind cross-over study in 8 volunteers. Rioprostil 50 and 100 micrograms reduced significantly (p = 0.45) the intensity (area under baseline) of the 0.5 g ASA-induced PD changes. Both doses reduced highly significantly (p = 0.003) the time taken for PD to return to baseline value (15.1 min with 50 micrograms and 17.2 min with 100 micrograms rioprostil vs 43.5 min with placebo). Both doses of rioprostil also reduced significantly (p = 0.04) the PD maximal drop induced by 1 g ASA and reduced highly significantly (p = 0.006) the time taken for PD to return to baseline value (18.9 min with 50 micrograms and 16.8 min with 100 micrograms rioprostil vs 64.6 min with placebo). This study shows that rioprostil protects the stomach against the ASA-induced alterations of the gastric mucosa even when it is given at the same time as ASA and in doses which have only a small antisecretory effect.