Cisapride is a potent pro kinetic medication used to stimulate the motility of the gastrointestinal tract. In the Chronic Kidney Disease (CKD) cat, it is the heavy hitter for managing severe Constipation and Megacolon.
The "Full Gut" Mover To understand why Cisapride is preferred over other drugs for constipation, you must understand where it works.
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The Limitation of Others: Drugs like Metoclopramide only work on the stomach and the very start of the small intestine. They stop working before they reach the colon.
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The Colon Activator: Cisapride stimulates smooth muscle along the entire length of the digestive tract, including the colon. This makes it the only effective oral drug for pushing hard, dry stool out of a dehydrated CKD cat.
The Mechanism (Serotonin Agonist)
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The Trigger: It binds to 5 HT4 receptors on the nerves in the gut wall.
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The Release: This triggers the release of Acetylcholine, the chemical that tells muscles to squeeze. It restores the rhythmic contractions (peristalsis) needed to move stool.
The "Compounding" Hurdle You cannot buy this drug at a regular pharmacy.
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Human Withdrawal: Cisapride was removed from the human market years ago because it caused fatal heart arrhythmias in people.
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Feline Safety: Fortunately, cats do not have the specific heart receptor that caused this problem in humans. It is safe for them.
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Availability: Because it is no longer manufactured commercially, it must be "compounded" (made from scratch) by a veterinary specialty pharmacy into capsules or liquids.
The Danger Zone (Obstruction) Just like Metoclopramide, the laws of physics apply.
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Contraindication: You must never give Cisapride if the cat is completely blocked (obstipation) and cannot pass stool at all.
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The Risk: If you stimulate the colon to squeeze against a rock hard blockage that cannot move, you risk rupturing the intestine. The blockage must often be removed manually (via enema) before starting Cisapride.
Side Effects
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Diarrhea: If the dose is too high, the gut moves too fast, causing cramping and diarrhea.
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Vomiting: Rarely, the increased motility can trigger vomiting or abdominal discomfort.
Disclaimer: This content is for educational purposes only and does not constitute veterinary medical advice. Always consult with your primary care veterinarian or a veterinary internal medicine specialist regarding your cat’s specific condition.