From the FDA Drug Label
DIRECTIONS FOR ADMINISTRATION Determine the appropriate dose for the body weight of the mare based on the dosing table below. One cc will treat 220 lb (100 kg) of body weight. Table 1 Dosing Table Weight(lb) Weight(kg) cc Domperidone(mg) 550-660 250-300 3 30 661-880 301-400 4 40 881-1100 401-500 5 50 1101-1320 501-600 6 60
The recommended dosage of domperidone for equine (horses) is based on the dosing table, which considers the body weight of the horse.
- For horses weighing 550-660 lb (250-300 kg), the recommended dose is 3 cc (30 mg of domperidone).
- For horses weighing 661-880 lb (301-400 kg), the recommended dose is 4 cc (40 mg of domperidone).
- For horses weighing 881-1100 lb (401-500 kg), the recommended dose is 5 cc (50 mg of domperidone).
- For horses weighing 1101-1320 lb (501-600 kg), the recommended dose is 6 cc (60 mg of domperidone) 1.
From the Research
The recommended dosage of domperidone for horses is typically 1.1 mg/kg orally once daily, which equates to approximately 550 mg for an average 500 kg horse. This medication is commonly used to treat fescue toxicosis in pregnant mares, agalactia (lack of milk production), and as a prokinetic agent to improve gastrointestinal motility. For pregnant mares, treatment should begin 30 days before the expected foaling date and continue until foaling occurs. For gastrointestinal motility issues, a 3-5 day course is often sufficient. Domperidone works by blocking dopamine receptors, which increases prolactin levels (improving milk production) and enhances gut motility. The medication is available as an oral paste or tablets specifically formulated for equine use. Side effects are generally minimal but may include mild colic or diarrhea. It's essential to note that domperidone does not enter the central nervous system significantly, making it safer than other dopamine antagonists like metoclopramide.
The most recent and highest quality study, 2, evaluated the effects of domperidone on the gastrointestinal tract of healthy horses and found that oral administration of 1.1 mg/kg of domperidone had no effect on gastric emptying, transit time, defecation frequency, or amount and moisture of excreted feces. However, another study, 3, found that oral administration of domperidone at 1.1 mg/kg significantly increased laminar microvascular blood flow, which may be beneficial in preventing vasoconstriction and reduction in blood flow believed to occur in horses with laminitis.
Key points to consider when administering domperidone to horses include:
- The dosage and duration of treatment may vary depending on the specific condition being treated and the individual horse's response to treatment.
- Domperidone should be administered orally, and the medication is available as an oral paste or tablets specifically formulated for equine use.
- Side effects are generally minimal but may include mild colic or diarrhea.
- It's crucial to consult with a veterinarian before administering this medication, as individual horses may require dosage adjustments based on their specific condition and response to treatment.
In terms of the medication's mechanism of action, domperidone works by blocking dopamine receptors, which increases prolactin levels (improving milk production) and enhances gut motility 4. The medication does not enter the central nervous system significantly, making it safer than other dopamine antagonists like metoclopramide. Overall, domperidone is a valuable medication for treating various conditions in horses, and its use should be guided by the most recent and highest quality evidence, such as the study by 2.