Antiulcer effect of rioprostil, a prostaglandin E1 analog, in combination with antacid

Rioprostil, a primary alcohol prostaglandin E1 analog, is currently undergoing clinical evaluation for use in the treatment of peptic ulcer disease. Since antacids are often used in conjunction with other antiulcer agents, studies were conducted to determine if concomitantly administered antacid modifies the antiulcer activity of rioprostil. This investigation showed that concomitant administration of antacid (0.25-1.0 ml Maalox) does not inhibit the ability of rioprostil (0.125-4.0 micrograms/kg, p.o.) to prevent ethanol-induced gastric lesions in rats. The antiulcer effect of the drug combination was additive, suggesting that each compound acts independently to prevent gastric bleeding. These results in animals suggest that clinically the use of antacid will not compromise the efficacy of rioprostil and that the combination may be a useful mode of therapy for the treatment of peptic ulcer disease.