Megacolon in Cats: Treatment
Megacolon occurs when a cat’s large intestine becomes excessively stretched and loses its ability to push stool toward the rectum. The result is severe, recurring constipation.
Treatment depends on how advanced the condition is.
1. Empty the colon. Severely constipated cats may require hospitalization, IV fluids, enemas, and manual removal of impacted feces under anesthesia. Never use sodium phosphate enemas in cats.
2. Keep stools soft. Polyethylene glycol (MiraLAX) or lactulose helps retain moisture in the stool. Dosages are adjusted to produce soft, easily passed bowel movements.
3. Improve intestinal movement. Cisapride stimulates colonic contractions and is often the most useful long-term medication. It works best before the colon has permanently lost its muscular function.
4. Adjust the diet. Some cats benefit from increased fiber, while others do better on highly digestible, low-residue diets. Advanced megacolon often responds poorly to added bulk.
5. Surgery. When medical management repeatedly fails, subtotal colectomy removes most of the dysfunctional colon. Most cats do remarkably well afterward, although loose stools may persist initially.
The bottom line: Early megacolon can often be managed medically. Advanced, irreversible megacolon frequently requires surgery. The goal is comfortable, regular defecation—not simply waiting for another obstruction.
Cisapride?
Absolutely cisapride, Doc! In fact, cisapride is one of the most important drugs for managing feline megacolon.
The distinction is whether the colon still has enough functional smooth muscle to respond.
- Early to moderate megacolon: Cisapride can be very effective at stimulating colonic motility.
- Advanced, chronic megacolon: The colon may become permanently dilated and atonic. Cisapride becomes much less effective.
- Severe fecal impaction: Empty the colon first. Cisapride isn’t a substitute for removing an obstruction.
Typical feline dose: 2.5–5 mg orally every 8–12 hours, sometimes increased to 7.5 mg or more in larger cats or refractory cases.
I would generally consider cisapride plus PEG 3350 or lactulose a reasonable medical approach, alongside appropriate dietary management.
The important point is that cisapride helps the colon move, while osmotic laxatives help keep the stool soft.
And one clinical pearl: Cisapride is much more useful before the colon becomes irreversibly dysfunctional.
