Is Cat Dewormer The Same As Dog Wormer

Dewormers are medications used to eliminate parasitic worms in pets like dogs and cats. They contain active ingredients that are toxic to intestinal worms and help remove them from the body. Deworming is an important part of preventative healthcare for pets as worms can cause a variety of health issues if left untreated. Some common worms that infect dogs and cats are roundworms, tapeworms, hookworms and whipworms. Dewormers come in oral and topical formulations and are available over-the-counter or may require a prescription from a veterinarian. The purpose of dewormers is to eliminate parasitic worm infestations and prevent reinfection by removing all stages of the worms from a pet’s body. Regular deworming keeps pets healthy by preventing worms from stealing nutrients, causing gastrointestinal issues, and spreading to humans.

Active Ingredients

The most common active ingredients found in cat and dog dewormers include:

  • Fenbendazole – An ingredient that treats roundworms, hookworms, whipworms and giardia in dogs. It is found in products like Safeguard Canine Dewormer (source:
  • Pyrantel Pamoate – Used to treat roundworms and hookworms in dogs and cats. Often combined with praziquantel.
  • Piperazine – Treats roundworms and tapeworms in dogs and cats.
  • Praziquantel – Used to treat tapeworms in cats and dogs. Also effective against fleas.

Many popular over-the-counter dewormers for pets contain a combination of these active ingredients to treat a broad spectrum of intestinal worms. It’s important to choose a dewormer specifically formulated for cats or dogs and to follow dosing guidelines.


There are some key differences between cat and dog digestive systems that influence how they process food and medications like dewormers:

Cats are obligate carnivores, meaning they rely on animal-based proteins and fats to thrive, while dogs are omnivores and can digest plant matter more efficiently. Cats have a shorter digestive tract designed for meat-eating, while dogs have a longer tract for digesting plants (Source).

a cat and dog illustration highlighting digestive system differences

Cats produce the enzyme taurine in their liver, which dogs don’t make enough of on their own. Taurine deficiency can cause heart and eye problems in cats if their diet is deficient (Source).

The pH level differs between cat and dog stomachs. Cats have a more acidic stomach pH around 1-2 while dogs are closer to 4-5. This effects how medications are absorbed and metabolized.

Cats have shorter intestinal tracts, so food passes through faster than in dogs. This means medications like dewormers may not have as long to be fully absorbed.

Overall, the differences mean dosage and formulations need to be tailored specifically for cats or dogs to be safe and effective.


A key difference between dog and cat dewormers is that some dog dewormers contain ingredients that can be toxic to cats (source). Using the wrong dewormer puts cats at risk of poisoning and other serious health issues.

One of the most concerning ingredients in some dog dewormers is piperazine. Piperazine is safe for dogs, but can cause adverse neurological effects in cats, including tremors, incoordination, and seizures. Even small amounts of piperazine can be dangerous for cats (source).

Other potential dangers of using dog dewormer in cats include vomiting, diarrhea, lethargy, and liver damage. The toxicity depends on the specific medication, dosage, and the individual cat’s sensitivity. Kittens and smaller cats are especially vulnerable.

In severe cases, using the wrong dewormer could lead to respiratory failure, coma, or even death in cats. Pet owners should be very cautious and always use products designed specifically for cats.


While many cat and dog dewormers contain the same active ingredients like pyrantel pamoate, there are differences in effectiveness when used across species. According to the Texas Pet Company, cat wormers often contain higher concentrations of certain active ingredients compared to dog wormers to account for metabolic differences between the species (Texas Pet Company).

For example, praziquantel is commonly used to treat tapeworms in both cats and dogs. However, cats may need a higher dose per pound of body weight to achieve the same efficacy as in dogs. This is because cats metabolize praziquantel faster than dogs (Pet Care Supplies).

Using a medication prescribed for a different species can lead to ineffective treatment if the dosage is too low. A study in the National Library of Medicine showed low palatability and intake of cat deworming tablets in dogs, indicating they may spit out the medication before ingesting the full dose (Bernachon et al.).

Ultimately, it’s important to follow label instructions and use dewormers formulated specifically for cats or dogs to ensure proper dosing and effectiveness against parasites. While the active ingredient may be the same, the concentrations cater to the needs of each species.


Cats and dogs require different dosages of dewormers due to differences in their size and metabolism. According to Texas Pet Company, “The dosing amount may also vary contingent on the size of the pet. There are a wide variety of products on the market that are species specific with clearly defined dosing based on the weight of the animal” (1). For example, the deworming medication pyrantel pamoate is often formulated into different doses for cats vs. dogs – a cat may only need 1/4 of a tablet while a medium sized dog requires a full tablet.

The dewormer dosage for a cat is typically much smaller than the dosage for a similarly sized dog. As noted by Hepper, “Even smaller dogs may still require a different dosage of active ingredients than cats. So dosing for a cat should be specifically outlined based on the weight of the cat” (2). Most dewormers provide a dosage chart with weight ranges for both cats and dogs, and the dosage for a 10 lb cat is lower than the dosage for a 10 lb dog.

It’s important to carefully follow label dosing instructions when deworming cats or dogs. Giving a cat medication formulated for a dog could lead to toxicity. Consulting a veterinarian is recommended to determine the appropriate dewormer and dosage for a specific pet.

Active Time

a cat being given oral medication

The amount of time a dewormer remains active in the body depends on the specific medication used. Most oral dewormers for dogs and cats only remain effective for a short period, which is why multiple doses are often required.

According to LabYES, oral anti-parasitic medications stay in a dog’s body for just a few hours before being eliminated. This is why veterinarians typically recommend administering a second dose of dewormer 2-4 weeks after the initial dose, to kill any newly hatched worms or eggs (1).

For cats, a single dose of an oral dewormer like pyrantel pamoate is effective at killing roundworms and hookworms in the body but only works for about 24 hours. So repeat dosing is needed to clear an infestation. Topical dewormers for cats can provide longer protection.

According to Emerald Life Pet Insurance, there are new sustained-release topical dewormers for dogs that remain active for 4 weeks when applied to the skin (2). These provide longer lasting protection compared to oral medications.

For humans taking anti-parasitic drugs, the medication typically starts working in 8-12 hours and remains effective for 24-72 hours according to Dr. Tran Phuoc Hoai (3). So the active time is relatively short unless multiple doses are taken.

Oral vs. Topical

When it comes to administering dewormers to cats and dogs, pet owners have two main options: oral medications or topical treatments. Oral dewormers come in chewable tablets or flavored pastes that are designed to mask the taste of the medication. These are administered directly into the animal’s mouth. Topical dewormers come in liquid form and are applied to the skin on the back of the neck, where the medication is absorbed into the bloodstream.

Oral dewormers provide the advantage of ensuring the full dosage is delivered, since owners can monitor the pet swallowing the medication. However, some pets dislike the taste or have difficulty swallowing pills. Topical treatments are very easy to apply but absorption through the skin can vary. There is also a risk of the pet licking off some of the topical before it fully absorbs.1

dog receiving topical dewormer treatment

Both oral and topical anti-parasite medications can potentially cause side effects like vomiting, diarrhea or lethargy in sensitive animals. It is important to carefully follow dosing guidelines based on the pet’s weight. Many leading products are safe for both cats and dogs when used as directed. Consult a veterinarian to determine the best deworming method for each individual pet.


There are several important warnings and precautions to consider when using dewormers on cats and dogs:

Using the wrong dewormer or improper dosage can make your pet sick. Dog dewormers often contain higher concentrations of active ingredients that can be toxic to cats if given in doses for dogs. Always use dewormers specifically formulated for cats when treating felines. Carefully follow label dosage instructions based on your pet’s weight.

Some dewormers can interact with other medications. Consult your veterinarian before using dewormers if your pet is on other medications or supplements. Stop giving heartworm prevention medication during treatment with some dewormers like ivermectin.

Do not use dog dewormers containing organophosphates like tetrachlorvinphos on cats – these insecticides are extremely toxic to felines. Signs of poisoning include drooling, vomiting, diarrhea, tremors and seizures.

Use caution when administering topical dewormers which can cause skin irritation. Monitor the application site for redness, sores or itching.

Pregnant or nursing pets may require different deworming protocols. Ask your veterinarian before deworming pregnant or nursing cats and dogs.

Some pets may experience mild side effects like lethargy or diarrhea after being dewormed. These effects are usually temporary but notify your vet if they persist.

Regular deworming is essential to protect your pet’s health and prevent reinfection. Follow your vet’s advice on the deworming schedule for your specific pet.

calendar reminder for pet deworming schedule


In summary, while cat and dog dewormers share some of the same active ingredients like pyrantel pamoate, there are important differences that make them unsafe to use interchangeably. Key differences include the strength of the active ingredients, which are dosed appropriately for each species. Using the incorrect dewormer can lead to ineffective treatment or toxicity. To keep your pets safe, always use dewormers formulated specifically for cats or dogs, as directed by your veterinarian. Never use dog dewormer on a cat or vice versa. When in doubt, consult your vet to ensure you are using the right dewormer at the right dosage for your pet.

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