Treating Constipation in Cats: Suppositories

Constipation is a serious problem in cats, and over the last two weeks we’ve taken an in-depth look at the factors that predispose cats to become constipated and some of the treatments. We’ve covered fluids, soluble and insoluble fiber, prebiotics & probiotics, Chinese herbs, and laxatives. Now, let’s consider suppositories.

How suppositories work
We resort to using suppositories when everything we’ve put down the throat hasn’t worked. Suppositories are wax or glycerine bullets that we slip into the rectum where they melt and stimulate defecation. Suppositories work in three different ways:

1. Lubricating—petroleum jelly
2. Hyperosmolar softening—glycerin, lactulose, and polyethylene glycol
3. Irritating—Dulcolax

Lubricating suppositories create a sliding surface inside the colon and over the feces so that stool slides out more easily. These suppositories are very gentle and can be used in almost all cats. Hyperosmolar suppositories pull water from the body to keep the stool moist. If cats are dehydrated, the hyperosmolar suppository will still pull water, and this increases the dehydration. Thus, hyperosmolar suppositories such as glycerine and lactulose lubricate the feces and the lining of the distal colon and others work by irritating the intestines and stimulating defecation.

Suppositories used for cats:

• glycerol,
• bisacodyl,
• docusate sodium.

Inserting suppositories
Cats have two circular sphincters, an outer sphincter called the anus, and an internal sphincter about 1 inch inside the anus. Suppositories are placed deep inside the internal sphincter not just deep to the anus.

Coming Up
We’ve covered 7 different treatments for constipation: fluids, soluble and insoluble fiber, prebiotics & probiotics, Chinese herbs, laxatives, and suppositories. We’ve been saving the big, nasty: enemas. We’ll cover giving enemas to cats next, and then we’ll cover medication.