Effects of cimetidine and ranitidine on basal gastric pH, free and total acid contents in horses.

This research article is about a study that examines the effects of two drugs, cimetidine and ranitidine, on the stomach acid levels in horses, discovering that these drugs can significantly reduce the gastric pH and acid contents, with ranitidine showing more potent results than cimetidine.

Overview of Research

• The research focuses on reviewing the effects of cimetidine and ranitidine on stomach acid levels in horses. It specifically observes the impact of these drugs on the baseline gastric pH, free acid, and total acid content.
• These measurements were taken from five adult horses at two-hour intervals for a period of between six and eight hours.

Observations and Findings

• Observations reveal that the baseline gastric pH, free acid, and total acid content varied between certain ranges, indicating that these levels are not constant but fluctuate within those limits.
• During the study, both cimetidine (8.8mg/kg orally) and ranitidine (2.2mg/kg orally) resulted in an increase in the gastric pH which surpassed 3.6. This brought about a concurrent 75% reduction in gastric free acid content over the eight-hour period.
• When administered intramuscularly, both drugs still increased the gastric pH to levels above 3.6, with cimetidine (4.4mg/kg) and ranitidine (1.4 mg/kg) reducing gastric free acid content by 54 to 93% and 69 to 100%, respectively, over the same eight-hour period.

Conclusions

• This study concludes that horses are basal acid secretors, meaning that they consistently produce stomach acid, even when not digesting food.
• It also concludes that both cimetidine and ranitidine, which are widely used as histaminergic-H2 type antagonists in human medicine, are also effective in horses.
• Of the two drugs, ranitidine was observed to be roughly four times more potent than cimetidine at reducing gastric acid levels.