Feline Constipation Treatment with Lactulose

Feline constipation is very uncomfortable, as your cat will find it difficult to pass stools. This condition presents itself when a cat has reduced, absent or painful defecation for more than a few days. Bowel movements become painful as the stool becomes hard and dry. Cats that are chronically constipated often have diarrhea and hence the condition can be diagnosed incorrectly. If feline constipation is left untreated for long or treated incorrectly, it can lead to complications.


Lactulose is the best known medication for feline constipation and must be prescribed by the vet. It is syrup that's made up of a long chain of indigestible sugars that help to soften stools by increasing the amount of water present in the colon. It's a polysaccharide created from two separate sugars (galactose and fructose), and is not absorbed in the intestine, but instead passes into the colon. When lactulose is fermented, it produces organic acids that stimulate fluid secretion in the colon. This colonic fluid acts as a laxative and helps to increase motility and volume of the feces which is then propelled out of the cat's system. Organic acids also attract ammonia caused by protein metabolism, and help it to migrate to the colon where it's metabolized to ammonium and excreted.


Lactulose should only be administered to the cat according to the veterinarian's instructions. In general, 0.5 ml of lactulose should be given initially for every kilogram of the cat's body weight. This dosage should be given two to three times a day. Dosage is dependent on the size of the cat and the severity of the constipation. However, care should be taken to avoid over-dosage as this can result in diarrhea or dehydration. The duration of administration of lactulose depends on the recovery of the cat and the development of any side effects. Even if your cat gets better, you should ensure that the treatment is completed as prescribed by the veterinarian, in order to prevent a relapse.

Recommended Precautions:

  • Lactulose should only be administered as prescribed by the veterinarian.
  • It shouldn't be given to cats that are allergic to it.
  • If it's administered in conjunction with other medication, your veterinarian should be informed of the same to prevent drug interactions.
  • Lactulose is contraindicated in diabetic cats.
  • It can cause adverse side effects such as diarrhea and dehydration. Hence, you should supply plenty of water to cats that are taking this medication.
  • It is also contraindicated in cats with electrolyte imbalances.

Availability of Lactulose

Lactulose is available in syrup form that contains 666 mgs per ml. However, cats aren't fond of the sweet tasting syrup. Therefore, it's best to incorporate it in the pet's food and camouflage the taste. Lactulose is available in powdered form as well. This mild-tasting powder can either be encapsulated or added to the food.

Cats of all breeds and ages can suffer from constipation. It's a common condition and can lead to complications such as weight loss, lethargy and vomiting. You should check the cat's litter box regularly and seek medical help at the earliest if your cat appears to be constipated.