FDA Notices

In your July issue, I learned the active drug in GastroGard is omeprazole. My spouse has just been taken off omeprazole because a new study from England found it was a major contributor to loss of bone. A bone-density study today revealed he now has severe osteoporosis.

Horse Journal Response: Several human studies have linked omeprazole to decreased bone density and increased risk of fractures in humans. However, this occurs in people that have been taking it for long periods of time (years), and the risk is definitely dose-related. The cause is inadequate calcium absorption because stomach acid is required to dissolve calcium that is in solid form, such as calcium supplements.

No studies have been done in horses to determine if the same risk exists. The acid-suppressing effect is similar in the two species, but horses also ferment their meals in the upper portion of the stomach. This produces organic acids that may help to counterbalance the effect of the drug. There are also probably very few horses that are left on a full dose of omeprazole for years at a time. Nevertheless, more study is warranted, particularly in growing horses and young racehorses where bone is very active and calcium requirements high.

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