Disadvantages of Long-Term Omeprazole Use in Horses

Omeprazole (a proton-pump inhibitor) is extremely effective for treating gastric ulcers in the squamous region of the horse's stomach. However, its long-term use—particularly when used continuously rather than in carefully managed treatment cycles—comes with significant drawbacks.

1. It Only Treats Stomach Ulcers, Not Hindgut Ulcers

Omeprazole suppresses gastric acid production in the stomach only.
Hindgut ulcers (right dorsal colitis, hindgut acidosis, cecal/colonic ulceration) are strongly associated with:

• High-starch feeds

• NSAID use

• Dysbiosis

• Stress and compromised mucosal integrity

Omeprazole provides no protection to the hindgut, and in horses with existing hindgut sensitivity, raising gastric pH may even shift fermentation patterns downstream, potentially worsening hindgut dysbiosis.

2. Rebound Gastric Hyperacidity (Acid Rebound)

One of the biggest clinical issues with long-term omeprazole use is rebound acid hypersecretion when the drug is stopped abruptly.

Mechanism:

• Omeprazole blocks acid production.

• The body compensates by increasing gastrin production.

• When omeprazole is withdrawn, the stomach produces far more acid than before.

Consequences:

• Rapid recurrence of ulcers

• More severe clinical signs

• Poor appetite, irritability under saddle, reduced performance

This is why tapering off omeprazole and supporting the gut during and after withdrawal is essential.

3. Reduced Nutrient Absorption

Healthy stomach acidity is required for:

• Activation of pepsin, the enzyme that digests protein

• Ionisation of minerals such as calcium, magnesium and certain trace elements

• Normal breakdown of forage and feed particles

Long-term acid suppression can lead to:

• Protein malabsorption

• Calcium and magnesium deficiency

• Compromised muscle function

• Reduced bone mineral density

• Poor coat and hoof quality over time

This is especially relevant to young, developing or actively training racehorses with high nutrient demands.

4. Bone Demineralisation

Research in multiple species—including emerging equine data—suggests chronic PPI administration can contribute to bone demineralisation through:

• Reduced calcium absorption

• Altered bone turnover rates

• Increased risk of microfractures or stress-related injuries

In performance horses, where bone density is paramount, this is a significant concern and is one of the strongest arguments against long-term PPI use.

5. Altered Gut Microbiome

A consistently higher gastric pH changes the entry environment for microbes.

Potential effects include:

• Increased survival of pathogenic bacteria entering the gut

• Disruption of the normal foregut–hindgut microbial balance

• Increased risk of colic or hindgut irritation

• Reduced fibre fermentation efficiency

Horses on long-term PPIs often show fluctuating faecal consistency, gassy behaviour or reduced hindgut stability.

6. Cost and Practicality

Omeprazole is very expensive to use long-term, especially at therapeutic doses for performance horses. Many owners keep their horses on "maintenance omeprazole," which:

• Is rarely necessary

• Is not supported by evidence

• May mask underlying management issues rather than resolve them

Comparison: Long-Term PPI Use vs. Daily Support with Immun-Ocean Gastro Race

Gastro Race is a multifactorial, natural, long-term digestive support supplement rather than a pharmaceutical acid suppressant. Its benefits are entirely different—and in many ways more applicable to maintaining long-term gut health.

1. Supports Both the Stomach and the Hindgut

Because it is based on Ascophyllum nodosum and Lithothamnium (marine algae rich in minerals, bioactive polysaccharides, natural buffers and prebiotics):

• Helps buffer stomach acid naturally

• Provides gentle alkalising support to the hindgut

• Reduces irritation across the entire GI tract

• Promotes mucosal healing and microbial balance

This holistic action matters for racehorses, which frequently have combined foregut and hindgut ulceration.

2. No Rebound Acid Effect

Gastro Race does not suppress gastric acid production, so:

• There is no rebound hyperacidity

• Horses can remain on it long-term safely

• It supports natural acid regulation rather than blocking it

This makes it suitable after completing an omeprazole treatment, during tapering or as a preventive strategy.

3. Enhances Nutrient Absorption Instead of Reducing It

The marine mineral complex improves:

• Calcium and magnesium bioavailability

• Enzymatic activity in the digestive tract

• Feed efficiency and nutrient uptake

• Overall metabolic and musculoskeletal health

This is especially important in horses with high physical demands.

4. Supports Bone Density and Joint Health

Lithothamnium is exceptionally rich in:

• Bioavailable calcium

• Trace elements

• Marine MSM from Ascophyllum

This combination naturally supports:

• Bone mineralisation

• Joint mobility

• Soft-tissue integrity

• Long-term structural soundness

This is the opposite of the potential bone demineralisation risk seen in chronic omeprazole use.

5. Balances the Microbiome

The natural polysaccharides, minerals and antioxidant components help:

• Stabilise the hindgut environment

• Feed beneficial bacteria

• Reduce stress-induced dysbiosis

• Support the immune system

This is critical in racehorses under training and travel stress.

6. Helps Manage Stress and Recovery

Magnesium, antioxidants, marine-derived amino acids and MSM may support:

• Nervous system balance

• Reduced cortisol response

• Improved post-race recovery

• Better appetite and demeanour

Summary: Why Long-Term Omeprazole Is Not Ideal — and Where Gastro Race Fits

By recognising the limitations of long-term omeprazole and choosing a more holistic, natural approach to digestive health, we give our horses not only relief from ulcers, but the foundation for stronger bodies, calmer minds and healthier performance for years to come.