Ask The Vet: How To Perform Deworming

Deworming your pet is paramount since one out of two animals are contaminated by worms. There are many species of parasites: Tapeworms extract nutrients directly from intestines. Others such as hookworms (like their name suggests) hook on the intestinal mucosa and suck the blood. There are also Dirofilarias which feed directly on plasma from the heart of the animal.

How to choose the dewormer?



Dewormers are not all made of the same molecule. They generally involve two complementary molecules that attack roundworms and flatworms simultaneously. However, some dewormers like Stronghold do not deal with all parasites. That’s why I recommend to use a complete dewormer that covers a large spectrum.

Keep in mind there are some dog breeds related to Collies (especially border collies and Australian shepherds) that are allergic to antiparasitics as a result of some genetic mutations (The Multi-Drug Resistance Gene MDR1). If your dog belongs to one of these breeds, it is necessary to seek help from a veterinarian in order to assess the risks.

Dewormer types


Many types of dewormers exist: pills, oral solutions, pipettes for dermal application (available only for cats), and injections.

For preventive purposes, go for a product that will allow you easier medicament administration. This of course depends on your animal’s character. I personally recommend pills as they are more and more palatable. Since animals have different taste preferences, do not hesitate to try a number of brands until you find the one your pet prefers. Also, pills’ action is faster compared to dermal applications.

Administration frequency


Generally speaking, animals that have access to the outside should be dewormed once every three months. For indoor pets, twice a year is enough.  Of course, deworming frequency depends on your very situation. For example, bimonthly administration is preferable for those who keep a group of pets, and in the case of pregnant women and immunodeficient owners.

 Administration timing

The best time is unarguably is the season change. I also recommend to perform deworming 15 days prior to vaccination. This permits the immunity system to make better vaccination response. If you have more than one pet, make sure you deworm them at the same time. Dewormers are not persistent, so dewormed animals can be easily re-infected.

When prevention doesn’t work, cure is necessary

In some serious cases, quick intervention is essential. Tenia infection can be dangerous. It is usually caught by flea ingestion when grooming.

I had to treat lately a quite severe case. A poor cat was suffering severe dehydration, cachexia (muscle atrophy) and hemorrhagic diarrhea. It turned out these symptoms were the consequence of Tenia infection. I decided to deworm the cat and prescribed her an anti-diarrheic treatment. I learned thereafter that the owner had Tenia herself. This case demonstrates the importance of regular deworming.