When you are at your vets for a routine visit, the veterinary surgeon will often ask you if your dog is up to date with its flea and worming treatment or would you like some while you are there. This is because dog wormers are an important subject for all pet owners. Often a lot of owners have questions about them, and it is a good chance to ask. Wormers are used to not only treat and kill any worms your dog may have. But also as a prevention to stop them from getting worms. But is “prescription-strength” always best?

Why is worming important?

Minimising your dog’s exposure to worms can be important for their health. As a worm burden can cause effects including diarrhoea, reduced appetite and vomiting. However, a more important reason to worm your dog is for human health; especially children who are most at risk because of touching soil contaminated with faeces that worms are passed in, and then touching their faces. Toxocara canis (roundworm) is a zoonotic (can pass from animals to humans) parasite that can cause organ damage, brain injury, or blindness as ingested worm eggs leave the intestine and crawl through the body. 

What do wormers protect against? And what types are there? 

Dog wormers protect against a wide range of worms depending on the active ingredient in them. The range they can prevent against is lungworm, roundworm, hookworms, whipworms, tapeworm and sometimes heartworm (not a problem in the UK, but infectious in some southern European countries). Sometimes these are combined with flea prevention to make treating your dog easier. 

There are worming liquids, often used in puppies due to their small size. And tablets which can be flavoured to help make them more palatable, or there are non-flavoured versions. Many can be crushed or broken in half to make them smaller. The amount needed will depend on the dog’s age and weight. 

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Prescription or non-prescription? What are the differences? 

Everywhere sells dog wormers; from the local pet shop to online stores as well as your Vets. However, even here there are important differences. NFA-VPS wormers – like Drontal, for example – cannot just be sold over the counter. They must be supplied by a registered pharmacist or a Suitably Qualified Person (a little bit like an animal pharmacist), who must check that they are suitable for the pet and the owner to use. Although not prescription, these are tested and effective drugs with a wide range of uses. They are usually sold in pet stores, food merchants, and pharmacies, and many vets will stock them too, for various reasons.

As against this, there are the AVM-GSL medicines which can be sold anywhere, to anyone, with no need for any checks. These are usually the least effective medicines, and have the most limited number of parasites which they will act on.

Key differences…

Some of the key differences can be the range of worms that are treated – some of the non-prescription ones, especially AVM-GSL (the “supermarket specials”!), do not treat all of the worms that your dog needs protection against. The non-prescription wormers also rely upon you knowing your pet’s weight. And often require you to get multiple tablets into your dog, especially if they are a large breed. 

While all wormer medicines must be safety tested, so you can be assured that they are safe to give, prescription and NFA-VPS wormers must also prove to a higher level that the active ingredient will work effectively to prevent or treat the worms. Prescription ones can also fit with flea treatments and combinations will have been deemed safe by the manufacturers and tested to ensure so. Therefore making it easier to treat everything without overuse. Worming treatments from your vets will also treat lungworm, whereas no non-prescription ones will. Depending upon your dog’s lifestyle this may be very important as lungworm can have very vague signs in affected dogs and can be fatal. 

Your dog will need to have been seen by your vet at the time of prescription for a prescription wormer. This is a legal requirement by the Royal College of Veterinary Surgeons, and the aim is to check your dog is healthy and therefore suitable to have worming products. 

However, an NFA-VPS wormer can be sold without the pharmacist, SQP or vet ever seeing your dog, so if your dog isn’t able to be brought into the surgery, these might be a better option.

How often to worm your dog is not a simple question to answer

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It depends on whether your dog is a scavenger, whether they are raw fed, where they are walked, what the local risk factors are, and also what flea treatment or other medication you are using for them. ESCCAP (European Scientific Counsel on Companion Animal Parasites) have produced guidelines for prescribers to follow. But these are also easily accessible to owners, explaining how often to worm depending on risk. However, there are also environmental consequences from overusing wormers. So we want to make sure we are using the right ones, at the right times, in the right animals, at the right doses.

It’s not the prescription wormer that you necessarily need…

It’s the consultation with the vet, who can help you decide what the risks are and what’s the best way to manage them for your pet and for you, as individuals. This might require a short consultation to get your dog checked over and everything explained to you. It is ultimately important for both your dog’s health and the wider human health to protect against worms in the most effective way possible.

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