Omeprazole is a commonly prescribed drug for gastric ulcers in horses, it is a Proton Pump Inhibitor or PPI, and has been until recently considered to be a safe drug, but recent information has come to light regarding the detrimental effects to health in long- term use. Omeprazole suppresses gastric acid which causes gastritis (inflammation of the stomach wall), omeprazole also stimulates the production of gastrin which is a potent growth factor known to cause hyperplasia of the enterochromaffin-like cells adding to the inflammation of the gut wall (gastritis). A healthy stomach pH creates an environment where the conversion of ingested nitrates (grass, forage, concentrates, water) to a safe form (n-nitrosation) is achieved by the released of ascorbic acid from healthy gastric mucosa, when this is missing, as in the case of long term use of omeprazole then the nitrates are converted to substances that are inflammatory and detrimental to the health of the gut wall. Omeprazole causes the proliferation of some bacteria which also increase the amount of nitrate within the stomach.
If your horse has had long term omeprazole, then increasing the amount of dietary plant anti -oxidants in the diet will help restore the integrity and health of the stomach. All plant anti-oxidants strongly promote the released of ascorbic acid. Diverse meadow communities are full of plants which are both anti- ulcerogenic and anti -microbial, two of the best are Shepherd’s purse (Capsella bursa-pastoris) and Chickweed (stellaria media). Both are good fresh or dried and can be offered as a daily hedgerow cutting mix for stabled horses.