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The Risks of Long-Term Omeprazole Use in Horses with Ulcers

The Risks of Long-Term Omeprazole Use in Horses with Ulcers

What is Omeprazole

Omeprazole, a proton pump inhibitor (PPI) used to treat gastric ulcers in horses, can affect mineral balance, particularly calcium absorption, and may have other impacts on mineral metabolism. While short-term use at preventative doses may not significantly impact bone density, long-term or higher-dose use could potentially lead to issues. 

1. Rebound Acid Hypersecretion (RAHS) 

Omeprazole suppresses gastric acid by inhibiting the proton pumps in the stomach’s glandular mucosa. When treatment stops suddenly, the stomach may overcompensate by producing more acid than before. This can increase ulcer recurrence risk unless the horse is weaned off gradually and feeding management is adjusted.

2. Altered Stomach and Gut Microbiome 

Acid suppression changes the stomach pH, which may allow bacteria and yeast that don’t normally thrive in the acidic stomach to proliferate. This altered microbial environment can affect digestion and possibly increase the risk of hindgut acidosis or colic in some horses.

3. Impaired Protein, Mineral, and Vitamin Absorption 

Acid plays a role in breaking down proteins and releasing minerals like calcium, magnesium, and iron from feed. Long-term acid suppression could reduce absorption efficiency, potentially contributing to mild protein maldigestion, micronutrient deficiencies over time (especially magnesium and calcium), and possibly secondary impacts on bone health in young or high-performance horses.

4. Masking the Underlying Cause 

Omeprazole treats the symptom (acid injury) but not the cause (e.g., high-NSC diet, long fasting periods, stress, intense exercise). If management changes aren’t made, such as increasing forage access, reducing starch, or altering training schedules, ulcers will likely return once medication stops.

5. Cost and Compliance Issues 

Long-term use is expensive and often leads owners to cut treatment short, which can cause incomplete healing. Horses sometimes relapse because they appear outwardly “better” but still have healing lesions internally.

6. Non-Medicated Alternatives

Research has shown that feeding turmeric (Curcumin xanthorrhiza) to horses with ulcers suppressed the formation of ulcers in the squamous region of the stomach. see  Pre-Treatment with Turmeric (C. Xanthorrhiza) Reduces the Severity of Squamous Gastric Ulceration in Feed Restricted Horses.   

 Ulcabuf is a non-medicated feed supplement based on Curcumin xanthorrhiza

Best practice for long-term management 

  • Use omeprazole for the vet-recommended course (usually 28 days full dose, then taper). 
  • Address root causes: more constant forage, reduced NSC, better stress management, and pre-exercise forage feeding. 
  • Feed low NSC, high DE feeds such as Coolstance copra
  • Consider a taper and transition to non-medicated ulcer supplements (e.g., Ulcabuf ) for maintenance.

ulcers ulcabuf omeprazole coolstance copra