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Lactulose Solution

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10 gm/15 ml 16 oz
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Product Info
How to Use
Customer Reviews
Product Info
What is Lactulose Solution?

Lactulose is used in cats and dogs as a laxative. Lactulose requires a prescription from your veterinarian.


Cats and Dogs

  • Liquid is easy to administer
  • No restrictions on food, drink, or activity unless otherwise directed by the veterinarian.
How it Works:

Lactulose is a disaccharide sugar composed of galactose and fructose. Unlike other sugars, its not absorbed into the blood. It passes unchanged to the large intestine. In the large intestine, lactulose is broken down by bacteria, resulting in the production of various acids. These acids draw water into the colon, softening the stool and increasing the volume, resulting in a laxative effect.


Side effects of lactulose include symptoms of flatulence, bloated stomach, and cramping. Diarrhea and dehydration are symptoms of overdose. Tell your veterinarian if your pet is diabetic, or pregnant or lactating.

Brand Name:

Chronulac or Cephulac (Hoeschst-Marion Roussel), Constulose or Enulose (Alpharma)

Generic Name:

Lactulose (lak-chew-lows)

What should I discuss with my veterinarian before giving lactulose to my pet:

Tell your veterinarian if your pet is diabetic. Tell your veterinarian if your pet is pregnant or lactating.

What is the most important information I should know about Lactulose:

Lactulose is a prescription medication that is not FDA approved for use in animals; however, it is a commonly accepted practice for veterinarians to use lactulose in dogs and cats as a laxative. Lactulose is available as a 10 Gm/15ml liquid. The usual laxative dose in dogs and cats is 1 ml per 2 pounds of body weight given every 8 hours initially, then use as needed. Notify the veterinarian if the pet develops excessive diarrhea.

How should this medication be given:

Give this medication exactly as directed by your veterinarian. If you do not understand the directions ask the pharmacist or veterinarian to explain them to you. Lactulose may be mixed with fruit juice, water, or milk to improve the taste. It may take 24 to 48 hours before the effects of lactulose are seen. Lactulose may darken slightly in color. This change is harmless. However, if lactulose becomes very dark or uneven in consistency do not use the product. Store lactulose at room temperature, away from moisture and heat. Keep this medication away from children and pets.

What happens if I miss giving a dose:

Give the missed dose as soon as you remember. However, if is almost time for the next regularly scheduled dose, skip the missed dose and take the next one as directed. Do not give a double dose of the medication.

What should I avoid while giving Lactulose to my pet:

There are no restrictions on food, drink or activity unless otherwise directed by the veterinarian.

What are the possible side effects of Lactulose:

If any of the following serious side effects occur, stop giving lactulose and seek emergency veterinary medical attention; an allergic reaction (difficulty breathing; swelling of the lips; tongue or face; hives). Other less serious side effects may occur. Continue giving lactulose and talk to your veterinarian if your pet experiences flatulence, abdominal cramps, diarrhea or nausea and vomiting. Other side effects may also occur. Talk to your veterinarian about any side effect that seems unusual or bothersome to the animal.

What other drugs will affect Lactulose:

Tell your veterinarian if your pet is being given an antacid as this may decrease the effects of lactulose. Drugs other than those listed may also interact with Lactulose. Talk to your veterinarian before giving your pet any prescription or over the counter medicines.

How to Use
  • Lactulose Solution is a prescription medication used in dogs and cats as a laxative.
  • Lactulose is also used to reduce blood ammonia levels in the prevention and treatment of hepatic encephalopathy.
  • Lactulose Solution is not FDA approved for use in veterinary medicine; however, it is a commonly accepted practice for veterinarians to prescribe this medication for dogs and cats.
  • Because Lactulose is a type of sugar (disaccharide) tell your veterinarian if your pet is diabetic.
  • Antacids may decrease the effects of Lactulose.

Lactulose may be mixed with water or milk to improve the taste. It may take 24 to 48 hours before the effects of Lactulose are seen. Notify your veterinarian if your pet develops excessive diarrhea.

All weights
The usual does is 1 ml for every 2 lbs of pet's body weight every 8 hours to start, or as directed by your veterinarian, then use as needed
Do not use!

Store at room temperature, away from heat and moisture.

Lactulose Solution:
Active Ingredients (per 15 mL)
10 g
Less than 1.6 g
Other sugars
Less than 1.2 g
Customer Reviews
Lactulose Solution is rated 4.7903 out of 5 by 62.
Rated 5 out of 5 by from This is an excellent product Our kitty was diagnosed with Mega Colon and had to have enemas fairly frequently. His stools were large and dry. He takes Cisapride (a tablet that we cut up and put into a gel capsule so it's easier for him to swallow). In addition, he takes 3ml. of Lactulose 3 times a day (1 dose before each meal). We give it to him using a syringe, but if your cat will eat food with meds in it, you can add it to your cat's food. Also, we add water to his canned food and feed dry food only as a treat. The dosage of lactulose can be increased if it appears your cat is constipated; but check with your vet to be sure he/she agrees. The lactulose keeps things "moving" along well and we get great service from 1-800-PetMeds so we never have to worry about running out.
Date published: 2015-08-31
Rated 5 out of 5 by from Great product My almost 17 year old cat has been on Laculose almost 2 years. His stool was so dry he was in emergency twice. Now that he has been on the medication, he is doing great, although he sometimes leaves me a 'nugget' outside of the box, but it's no longer dry and hard. I hope he lives another couple years but for now he's doing great.
Date published: 2015-01-30
Rated 4 out of 5 by from Lactulose was first prescribed for Lusy because she has a portal shunt of her liver. She does very well with it and it seems to agree with her fragile system. She is a laid back spoiled little girl!
Date published: 2014-12-23
Rated 5 out of 5 by from my cat needs this med Buddy was on deaths door with a sever blockage in his colon. With my vets help and lactulose solution he is in great health now. He will probably need to be on this medication for the rest of his life. Thank you pet meds for allowing me to purchase it in large amounts at an affordable price.
Date published: 2014-12-22
Rated 5 out of 5 by from Gets the job done Our big cat with mega colon hates Lactose and puts up a fight (with claws), when administered orally, but it really gets the job done. He doesn't eat it if mixed with food. We told him it was either this stuff or his life was going to be short-lived. It takes 2 of us to administer 6 cc daily. Without Lactulose solution, he would be totally blocked. He's 9 years old - acts like a kitten when he's regular - and really a loving and precious guy. I'm so greatful for this product, which I understand is safe for long-term use. I rate this product "5" for effectiveness, but not for taste (sweet syrup) and ease of use.
Date published: 2014-08-22
Rated 5 out of 5 by from My (rescue) Lab Maggie has hepatic encephalopathy due to a damaged liver of unknown causes-- so her liver can no longer process protein, therefore the ammonia levels build up in her blood causing life threatening problems-- after a week in the ER hospital it now is under control with diet and 2 to 3 doses of lactulose daily to remove the ammonia. I am very happy with the results, she will have to remain on this medication for the rest of her life, thank goodness it is working for her and doing exactly what it is suppose to do-- I definitely recommend this product for this problem.
Date published: 2014-07-22
Rated 5 out of 5 by from Best product I've ever used! Little Bitz is a rescue cat who would not be alive without this medication. It's so easy to mix in with his food that he doesn't even know it's there. This has kept him happy and very healthy for 4 years now. We tried other products but this is by far the most efficient and convenient.
Date published: 2014-07-05
Rated 5 out of 5 by from Lactulose really helps! My cat Skunky is 14 years old. She developed cirrhosis of the liver several years ago. As long as she takes her Lactulose once a day, she does well. If she experiences difficulty, I give her an extra dose in the evening. She also had diabetes, but it has been cured due to her high protein diet. She acts like a kitten now.
Date published: 2014-05-11
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Can giving a cat Lactalose make her diabetic?

My 10 year old cat has had chronic constipation for about two years. I have found that by giving her Lactulose, it has somewhat helped. My vet said that the only side effects would be diarrhea, if I gave her too much. I currently give her lactulose along with Vetasyl, which is a fiber pill and it is finally working. Recently she has been diagnosed to have diabetes. I can't help thinking that the lactulose I gave her is the reason that she became diabetic. Could I have unknowingly done this to her? My vet said no, but I keep having this nagging feeling.
Asked by: Deb
What does your vet say? We've used it for several years, and our cat has not developed diabetes.
Answered by: Sunny's mom
Date published: 2015-09-01

Can lactulose be used in cats with diabetes?

Asked by: Puff
This medication should be used with caution in diabetic patients.
Answered by: Stephanie Duesler, Pharm. D, MBA
Date published: 2015-03-26

is there anything a cat can be given to reduce the bloating and crampy side effects?

My cat has a tumor on her colon which is pressing on the colon and restricting the passage. She needs to take lactulose to help keep her stool soft enough to pass. It works. but makes her feel lousy with bloating and possible cramping. What can she take to reduce these symptoms?
Asked by: siouxbear
Please consult your veterinarian, as they may be able to find the best treatment option for your pet to ensure your pet is comfortable.
Answered by: Stephanie Duesler, Pharm. D, MBA
Date published: 2015-03-26

How may CC's do you give Lactulose to a 6 Lb 3 year old Dog?

How many cc's would one give to 3 year old 6 lb. Mi-Ki? Lactulose, liquid, gold in color and thick like a pancake syrup
Asked by: KitKat
Only your veterinarian can prescribe the amount of lactulose to give your pet.
Answered by: Kelly P
Date published: 2014-09-30


Is this version (the one sold on 1800petmeds) unflavored? The version I got from my vet is pina colada flavored which is not great for cats.
Asked by: moemurphy
This product does not have any particular flavoring.
Answered by: Lilli Pharmacist
Date published: 2014-08-20

Can you tell me how much a month's supply of duphalac (lactulose) would cost if I give my cat 4ml. three times a day?

He has been on this drug along with cisapride for three years for mega colon.
Asked by: judy
My cat too has mega colon, and is taking cisapride with lactulose. In the begining he also was taking it multiple times a day, but he developed diarrhea so now I only give him his pill and 3ml of lactulose in the morning. I also greatly reduced his dry food intake which causes dry stools and give him canned food which is mostly water which is what they need in them to not get constipation I buy 2 bottles at a time. I suggest you call PetMeds and they can estimate the cost for you. They have THE BEST price for this medication.
Answered by: Jane
Date published: 2013-03-01

Is the Lactulose sold for pets any different to what is sold for human use? Could the Lactulose sold for human use cause Hypercalcemia in a cat?

Asked by: Anonymous
The Lactulose that I get from PetMeds is not any different from the type that you would get from a pharmacy for people. I have had this medication from my doctors prescription for constipation and found out from him that it's the same stuff, just that the pharmacy dispense it in smaller quantities.
Answered by: Jane
Date published: 2013-11-16

Could Lactulose be given to a cat permanently ?

Under what conditions would Lactuose be given to a cat for an extended amount of time? Possibly on a permanent basis?
Asked by: jacque
Yes, Lactulose can be given to a cat on a permanent basis. My four year old cat will have to take Lactulose for the rest of her life. This was per my vet. If I stop the medicine, the problem will reoccur. She has cronic constipation. Make sure to give your cat a dosage recommended by your vet.
Answered by: Noelle's Mom
Date published: 2012-12-22
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