An interesting read about the impact of proton pump inhibitors (PPI) like Omeprazole (the major drug we use to treat equine gastric ulcer syndrome) on the gut bacteria in humans! https://gut.bmj.com/content/early/…/12/09/gutjnl-2015-310376
While these drugs are a huge help in setting up an environment in the equine stomach where ulcers can heal, they are overused in many horses (some racehorses are never taken off these drugs) to prevent ulcers in place of management systems that will reduce a horses risk of ulcers (like feeding a forage meal to fill the stomach prior to work).
Makes me wonder what PPIs may be doing to the equine gut bacterial populations… one study I can find (https://onlinelibrary.wiley.com/doi/pdf/10.1111/eve.07_12792) shows no impact on equine fecal bacterial populations, but use of omeprazole in these horses was only short term and the study doesn’t specify the dose used. The fecal microbiota also aren’t necessarily reflective of what is happening further up the gastrointestinal tract.
Something to keep in mind if you have a horse on a PPI medication long-term. Needs some more research!