How Long Does Dewormer Take to Work on Cats?

Like any animal, cat’s are susceptible to parasites and pests which can have an adverse effect on their health.

These include fleas and more specifically to this article, worms.

Worms affect cats in different ways, potentially causing  infections in the stomach, intestines and skin. Severe cases can prove fatal.

How Long after DeWorming a Cat are the Worms Gone?

Hookworms and tapeworms can be killed by giving a single dose of an appropriate medication.

In most cases, the worms will be eliminated after about three days although it can often take up to nine. The length of time it takes to eradicate your cat’s worms can depend on:

  • Type of Worm Infestation
  • Number of Worms Present
  • Worm’s Resistance to Treatment

How to Cats Get Worms?

Cats can get worms from a variety of sources. Worms can be passed from the mother to the kittens during birth. They can also be caught from other animals or from food.

Cats might also be exposed to fleas or ticks which carry worm eggs. Poor hygiene and sanitation are known to cause worms as well.

Types of Worms That Affect Cats

Multiple worm species can infect cats, among them roundworm, hookworm and tapeworm.


Rondworms live within the intestine of a cat and are especially common in kittens. They’re transmitted through feces or when the cat ingests infected animals such as birds and rodents.


Hookworms are tiny and live in the gut, attaching themselves to the walls of their host’s intestines.

Cats can get hookworms from coming into contact with fleas or infected particles found in cat feces.


Tapeworms are intestinal parasites that are usually transmitted when the cat comes into contact with fleas.

They look like segmented, ribbon-like tubes with scaly heads at both ends.


Heartworms can be transmitted via the bite of an infected mosquito.

It lives in the cat’s heart or lung and can cause serious health problems.

Although the heartworm can affect felines, its much more prevalent in dogs.

What are the Symptoms of Worms in Cats?

While it’s not always obvious that your cat is suffering from worms, there are some of the common symptoms you should look out for:

  • Weight loss
  • Lethargy
  • Poor Appetite
  • Bloating
  • Diarrhoea
  • Fever
  • Constipation
  • Dehydration

Different Types of Cat DeWormers and How They Work

Cat wormers provide relief from the symptoms of worms and may also prevent them from coming back.

A lot of cat dewormers come in the form of tablets, although liquid and injectable medications and are also widely available as over the counter treatments.

Common ingredients found in de-wormers include:


This is a type of anthelmintic drug that kills the larvae o  intestinal roundworms, hookworms and tapeworms. Side effects are minimal although vomiting can result on occassion.


Ivermectin paralyzing worms, causing them to stop feeding. The worm usually dies within hours. Ivermectin works on all types of worms, killing the eggs and larvae.


Praziquantel kills roundworms as well as other parasites like fleas.

It works by blocking the production of an essential protein in the tapeworm’s cell wall which prevents the worm from groing.

After its killed, the remains are passed in the cat’s feces.

Pyrantel Pamoate

Pyrantel Pamoate is used to treat and prevent roundworm and hookworm infestations in dogs and cats.

Pyrantel Pamoate works by disrupting the nerve impulses that cause the worms to contract, causing paralysis and death.

Once they detach from your cat’s intestine walls, they’re passed in the cat’s stool. Administered orally or topically, Pyrantel Pamoate can also be mixed with your cat’s food.


Piperazine is a chemical compound that kills worms by paralyzing them. It has been used as a pesticide for decades.

But it was not until fairly recently that people realised its potential in eradicating cat worms, specifically roundworms. It’s available in the form of tablets, capsules, powders, and liquid.

Specialists That Sell Cat De-Wormers

Pet Drugs Online

Pet CareRx

Budget Pet Care

What are the Side Effects of Cat De-Wormers

De-wormer side effects will vary according to the type of medication and the extent of the dosage. Some of the most common side effects include:

  • Vomiting
  • Diarrhoea
  • Drooling
  • Loss of Appetite

Tips for Preventing Worm Re-Infection in Cats

To prevent re-infection, the following steps will help to ensure that your pet remains free of worm infectations.

  • Keep Your Cat Indoors
  • Regular Re-Worming Regimen
  • Maintain Good Litter Tray Sanitation
  • Regular Flea Treatment
  • Maintain Good Cat Hygiene
  • Disinfect Water and Food Bowls
  • Clean Up Cat Faeces Thoroughly

Everything You Need to Know About Cat Deworming

Useful Links

Cornell University – Gastrointestinal Parasites in Cats

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