Cisapride
Cisapride is a potent gastrointestinal prokinetic agent used primarily in veterinary medicine to manage conditions like **feline megacolon**, **gastric stasis**, and **reflux esophagitis**. > **Clinical Pearl:** Due to severe cardiac arrhythmias (QT prolongation) in humans, cisapride was voluntarily removed from the human market. It is now exclusively available for veterinary patients through **compounding pharmacies**. Despite the cardiac risks in humans, it is generally very well tolerated in dogs and cats. It is highly effective at stimulating motility from the esophagus down to the colon, making it a cornerstone therapy for chronic constipation in felines.
Mechanism: Cisapride acts primarily as a **serotonin 5-HT4 receptor agonist** in the gastrointestinal tract. * **5-HT4 activation** โ stimulates the release of **acetylcholine** at the myenteric plexus. * This increases lower esophageal sphincter pressure, enhances esophageal peristalsis, and accelerates gastric emptying and colonic motility. * Unlike metoclopramide, it has minimal dopamine receptor blockade (no extrapyramidal effects) and does not stimulate gastric acid secretion. * Acetylcholinesterase activity is not inhibited.
Dosing by species
- For chronic constipation (e.g., megacolon) ยท 2.5 mg (for cats up to 10 pounds) or 5 mg (for cats 11 pounds or heavier) three times daily, 30 minutes before food. Cats weighing greater than 16 pounds may require 7.5 mg. ยท PO ยท q8h ยท In combination with a stool softener and a bulk agent.
- For chronic constipation (e.g., megacolon) ยท 1.25-2.5 mg per cat two to three times a day ยท PO ยท q8-12h ยท Cats with hepatic insufficiency should be treated with half the usual dose; probably most effective when given 15 minutes before a meal.
- For chronic constipation (e.g., megacolon) ยท 2.5-5 mg per cat PO q8-12h ยท PO ยท q8-12h
- For chronic constipation (e.g., megacolon) ยท 5 mg per cat (total dose) PO q8-12h ยท PO ยท q8-12h
- For gastric stasis ยท 0.1 mg/kg PO two to three times daily; cats tolerate 2.5 mg doses without problems ยท PO ยท q8-12h
- To reduce the risk for esophageal stricture formation in cases of esophagitis ยท 0.5-0.75 mg/kg PO three times daily. ยท PO ยท q8h
- As a promotility agent (Foals with periparturient asphyxia) ยท 10 mg (total dose) PO q6-8h. ยท PO ยท q6-8h ยท Adequate time for healing of damaged bowel before using prokinetic agents is essential.
- Promotility (Mice, Rats, Gerbils, Hamsters, Guinea pigs, Chinchillas) ยท 0.1-0.5 mg/kg PO q12h ยท PO ยท q12h
Routes of administration
Contraindications
- Gastrointestinal perforation
- Gastrointestinal obstruction
- Gastrointestinal hemorrhage
- Hypersensitivity to cisapride
Adverse effects
- Vomiting
- Diarrhea
- Abdominal discomfort
- Prolonged QT intervals or cardiac arrhythmias (very rare in veterinary patients)
Drug interactions
- Anticholinergic agents ยท May diminish the prokinetic effects of cisapride.
- Benzodiazepines ยท Cisapride may enhance the sedative effects of benzodiazepines.
- Warfarin ยท Cisapride may enhance anticoagulant effects; additional monitoring and dosage adjustments may be required.
- Oral drugs with a narrow therapeutic index ยท Cisapride decreases GI transit times, potentially altering the absorption of other oral drugs. Serum levels may need closer monitoring.
- CYP3A4 Inhibitors (Amiodarone, Ketoconazole, Itraconazole, Fluconazole, Chloramphenicol, Cimetidine, Fluvoxamine, Grapefruit juice, Macrolides except azithromycin) ยท Inhibit cisapride metabolism, leading to increased cisapride levels and an increased risk for cisapride cardiotoxicity.
- QT-prolonging drugs (Amiodarone, Clarithromycin, Moxifloxacin, Procainamide, Quinidine, Sotalol, Tricyclic Antidepressants) ยท May increase the risk of QT interval prolongation and fatal arrhythmias when used concurrently with cisapride.
Monitoring
- Efficacy (resolution of GI stasis, constipation, regurgitation)
- Adverse effects profile (GI upset, signs of arrhythmias)
Overdose
LD50 doses in various lab animals range from 160 - 4000 mg/kg. The reported oral lethal dose in dogs is 640 mg/kg. **Clinical Signs:** Most common adverse effects seen in dogs and cats are diarrhea, lethargy, ataxia, hypersalivation, muscle fasciculations, agitation, abnormal behavior, hyperthermia, and possibly seizures (dogs). **Treatment:** Significant overdoses should be handled using standard gut emptying protocols when appropriate. Supportive therapy should be initiated when required. **Activated charcoal** is effective in binding unabsorbed cisapride.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturerโs current label.