Lactulose for Cats and Dogs (Constulose®, Enulose®, Generlac®, Kristalose®)
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Lactulose is a laxative commonly prescribed to treat constipation in dogs and cats. Veterinarians also use it to help lower ammonia levels in pets with hepatic encephalopathy caused by liver disease.
Here’s how lactulose works, when it’s prescribed, possible side effects, dosing guidance, and important safety information.
Key Takeaways
- Lactulose is commonly used to treat constipation in dogs and cats.
- It also helps lower ammonia levels in pets with hepatic encephalopathy.
- Lactulose works by drawing water into the colon to soften stool and by trapping ammonia for elimination.
- Diarrhea and dehydration are the most common side effects if too much is given.
- Always give lactulose exactly as directed by your veterinarian.
What Is Lactulose?
Lactulose is a laxative used to treat constipation in cats and dogs. It is also prescribed to help prevent and treat hepatic encephalopathy by lowering ammonia levels in the bloodstream.
FDA approval: Lactulose is FDA-approved for human use under the brand names Constulose®, Enulose®, Generlac®, and Kristalose®.
Lactulose is not FDA-approved as a veterinary medication. However, veterinarians may legally prescribe it extra-label (off-label) for dogs, cats, and other animals when appropriate.
How Lactulose Works
Lactulose works by drawing water into the colon to soften stool and by helping remove excess ammonia from the body.
Lactulose is a sugar that mammals and birds cannot digest. It passes unchanged into the colon, where normal intestinal bacteria break it down into acids, primarily lactic acid (along with acetic and formic acid).
These acids draw water into the colon through osmosis, softening the stool and making it easier to pass.
Lactulose also helps pets with liver disease. When the liver cannot effectively remove ammonia from the bloodstream, ammonia levels can build up and contribute to seizures or other neurologic signs.
The acids produced when lactulose is broken down create an acidic environment in the colon, causing ammonia to move from the bloodstream into the colon, where it becomes trapped in the stool and is eliminated from the body.
How To Give Lactulose
Give lactulose exactly as directed by your veterinarian.
Lactulose is commonly given three to four times daily, although the exact dosing schedule varies depending on your pet's condition and response to treatment. Always follow the directions on the prescription label and your veterinarian's instructions.
Missed a Dose?
If you miss a dose of lactulose, give it as soon as you remember. However, if it is almost time for your pet's next scheduled dose, skip the missed dose and resume the normal dosing schedule.
Do not give extra or double doses.
Lactulose Side Effects
Lactulose is generally well tolerated, but side effects can occur, most commonly affecting the digestive system.
Possible side effects include:
- Flatulence
- Stomach distension (bloating)
- Abdominal cramps
- Diarrhea
- Dehydration
Human Side Effects
Although lactulose is also used in people, human and veterinary dosing may differ.
If you accidentally ingest lactulose prescribed for a pet, contact your physician or your local Poison Control Center.
Monitoring Your Pet
No specific monitoring is required while your pet is taking lactulose. However, your veterinarian may recommend routine testing, particularly to monitor electrolyte levels, based on your pet's condition, other medications, and the reason lactulose was prescribed.
When To Call Your Veterinarian
Contact your veterinarian if:
- Your pet develops severe side effects.
- You suspect your pet has received an overdose.
- You have additional questions or concerns about using lactulose.
Lactulose Overdose
A lactulose overdose most commonly causes excessive gastrointestinal side effects and may lead to dehydration.
Signs of an overdose may include:
- Diarrhea
- Dehydration
- Flatulence
- Abdominal cramping
If you suspect your pet has received an overdose, contact your veterinarian immediately or an animal poison control center. Consultation fees may apply.
- Pet Poison Helpline: (855) 764-7661
- ASPCA Animal Poison Control: (888) 426-4435
How To Store Lactulose
Store lactulose according to the product label to help maintain its safety and effectiveness.
Storage instructions:
- Store lactulose at controlled room temperatures between 68 F and 77 F (20 C–25 C).
- Always confirm storage instructions by reading the product label.
- Store the medication in a light-resistant container.
- Keep out of reach of children and pets.
Lactulose for Cats and Dogs FAQs
How much lactulose can you give a cat?
The correct dose of lactulose depends on your cat's condition and response to treatment.
Lactulose is commonly given three to four times daily, but both the dose and frequency are adjusted based on your cat's individual response. If your cat develops diarrhea while taking lactulose, contact your veterinarian because the dose may need to be adjusted.
Is lactulose harmful for cats?
No. Lactulose is generally considered safe for cats when used as directed by a veterinarian.
It is commonly prescribed as a stool softener for constipation and to help lower ammonia levels in pets with hepatic encephalopathy.
What does lactulose do for cats?
Lactulose softens stool to help relieve constipation and lowers ammonia levels in cats with hepatic encephalopathy.
Is Kristalose® the same as lactulose?
Yes. Kristalose® is a brand-name product that contains the active ingredient lactulose.
However, Kristalose® is available in a different concentration than Enulose®, which is the brand most commonly used in veterinary medicine.
Can dogs take lactulose?
Yes. Veterinarians commonly prescribe lactulose for dogs to treat constipation and help manage hepatic encephalopathy.
Can lactulose be given with food?
Follow your veterinarian's instructions. Lactulose may be given with or without food unless otherwise directed.
How long does lactulose take to work in cats?
Response time varies depending on your cat's condition and the reason lactulose was prescribed. Your veterinarian may adjust the dose based on your pet's response.
No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.
