From the Research
Combining hydroxyzine with cetirizine in horses is not generally recommended as a standard practice. Hydroxyzine and cetirizine are both antihistamines that work through similar mechanisms, so using them together provides limited additional benefit while potentially increasing the risk of side effects 1. If antihistamine therapy is needed for conditions like urticaria or allergic dermatitis in horses, it's preferable to use one antihistamine initially and assess the response before considering alternatives.
Key Considerations
- Hydroxyzine tends to cause more sedation in horses, while cetirizine is less sedating but may be less effective in some cases.
- The combination could potentially increase anticholinergic side effects including dry mucous membranes, urinary retention, and gastrointestinal motility issues.
- Always consult with an equine veterinarian before administering these medications, as individual horses may have different needs based on their specific condition and health status.
Alternatives to Combination Therapy
- If a single antihistamine is ineffective, consider adding a different class of medication such as corticosteroids rather than a second antihistamine.
- Cetirizine has been shown to be effective in treating allergic disorders with minimal sedation and anticholinergic side effects 2, 3, 4.