In veterinary medicine, Domperidone (DOM) is a versatile pharmacological agent primarily utilized for its prokinetic (enhancing gastrointestinal motility) and hyperprolactinemic (stimulating milk production) properties.

The following is a comprehensive synthesis of its applications, ranging from mammalian clinical use to aquatic breeding programs.

1. Core Pharmacological Mechanism

Domperidone acts as a peripheral dopamine (D~2~) receptor antagonist. Its primary advantage in animals is its inability to cross the blood-brain barrier significantly, resulting in fewer central nervous system (CNS) side effects compared to older drugs like Metoclopramide.

• In Mammals: It blocks dopamine's inhibitory effect on prolactin, leading to increased milk production.
• In Fish: It blocks dopamine's inhibitory effect on the pituitary gland, allowing for the release of Gonadotropin (GtH).

2. Dual-Field Applications

A. Mammalian Veterinary Medicine (Equine, Canine, Feline)

In these species, Domperidone is often used as a monotherapy (used alone).

• Agalactia (Milk Failure): Specifically in mares suffering from fescue toxicosis. The ergot alkaloids in fescue grass mimic dopamine and suppress lactation; DOM reverses this.
• Gastrointestinal Motility: Used in dogs and cats to treat delayed gastric emptying, gastroesophageal reflux, and chronic vomiting.

B. Aquaculture (The "LINPE" Method)

In fish breeding, DOM is rarely used alone. It is almost always combined with GnRHa (Gonadotropin-Releasing Hormone analogues), commonly referred to in China as A2 or A3.

• The Combination Logic:
  • A2/A3 (The Accelerator): Directly stimulates the pituitary to produce reproductive hormones.
  • DOM (The Brake Release): Removes the "dopaminergic brake" that prevents hormone release.
• Synergy: This combination is the gold standard for induced spawning in carps, catfish, and various ornamental fish.

3. Comparison of Use Cases

4. Technical Administration & Dosage

In aquaculture, the dosage is strictly weight-dependent. A common formula for the total required dose (D~total~) for a population of fish with weight (W) is:

5. Critical Precautions

• Contraindications: Never use DOM if a mechanical bowel obstruction or perforation is suspected, as stimulated motility could lead to a fatal rupture.
• Cardiac Warning: While rare in animals, high doses may impact cardiac repolarization; use with caution in animals with pre-existing heart conditions.
• Storage: Most veterinary DOM preparations are light-sensitive and should be stored in cool, dark environments.

Summary: Whether you are managing a nursing mare or managing a fish hatchery, Domperidone serves as the essential tool to "unlock" the animal's hormonal potential by neutralizing dopamine interference.