What wormers are best for dogs?

If you look around the internet, or the Pet Health shelves of a supermarket or pet shop, you’ll see that there’s a dazzling array of different worming products available. You’ll also notice a big divide – by and large (with a few honourable exceptions), the wormers you see in our practice, and that our vets recommend, are not the ones you see advertised elsewhere.

This is because the most potent and effective drugs are regulated more tightly than weaker or less powerful ones. As vets, we want to use the most effective and safest products, so we tend to rely on these more modern drugs.

What worms are we worried about?

There are two main families of worms we need to worry about treating in our dogs – the roundworms and the tapeworms. Some drugs kill both, but most kill only one sort or the other; this is why the most effective wormers on the market contain two or more different ingredients.

So, what types of wormers are there?

There are a huge range of possible active ingredients! However, they can be divided into a number of groups, based on where they can be sold and who by.

  • Herbal products, e.g. garlic tablets
    • These have been used for many centuries; however, there are significant risks. Garlic, for example, may have a (rather weak) action against worms, but is also toxic to dogs, potentially causing severe anaemia. Dog-safe garlic powder is available, and has the toxic components removed – but as a result appears to have very little effect on worms either.
    • As a result, we can’t recommend the use of garlic and herbal wormers – they just aren’t safe enough, or strong enough, to be worthwhile!
  • Homeopathic remedies
    • Homeopathic remedies, unlike herbal ones, are a recent invention, dating back only to the nineteenth century, based on the premise that “like cures like” if diluted to the point where there is none of the original product present in the medication or nosode.
    • Sadly, there is no evidence of any benefit and no detectable reduction in worm counts in animals treated with homeopathic wormers.
  • Over-the-counter medications
    • These can be bought at any supermarket or shop, and there is no restriction on their sale. Legally, they are classified as AVM-GSL (authorised veterinary medicine, general sales list).
    • They often contain only relatively weak active ingredients (such as piperazine, a very old fashioned drug that doesn’t kill worms but paralyses them, making it more likely that they are passed out in the faeces; found in Beaphar Worming Syrup and Johnson’s Puppy Easy Worm, among others).
    • Other over the counter wormers contain active ingredients which are very powerful and potentially toxic but are only present in very, very low doses (such as nitroscanate in Beaphar One Dose Wormer and Bob Martin Clear Wormer).
    • However, there are also more potent drugs available through this route – a few products, such as Beaphar WORMclear and Bob Martin Clear 3 in 1 Wormer, do actually contain fairly effective ingredients (in this case, febantel, praziquantel and pyrantel – a good broad-spectrum wormer active against tapeworms and roundworms).
    • There are also some very potent anti-tapeworm drugs available over the counter, containing the drug praziquantel (such as Bayer Praziquantel Tablets).
    • The problem (as you’ve probably already seen!) is that wormers with very, very similar brand names may have very, very different active ingredients. For example, Bob Martin Clear Wormer and Bob Martin Clear 3 in 1 Wormer are completely different drugs!
  • Pet shop / non-prescription veterinary wormers
    • These can only be sold from certain registered premises (such as vets’, farm merchants and some pet shops), and there must be a qualified person on the premises (an SQP, who is trained by AMTRA to supply these products). They are classified as NFA-VPS (non-food animal, veterinarian, SQP or pharmacist).
    • These products need to have proven that they are not only safe, but effective.
    • These usually contain a combination of drugs (often febantel or oxantel, praziquantel and pyrantel) to give a very effective kill of both roundworms and tapeworms, and include brands such as Cestem, Drontal, and Quantilex.
    • There are also single-ingredient products, that are effective only against roundworms, such as fenbendazole – found in Granofen and Panacur, among others.
  • Prescription-only veterinary wormers
    • These are the most powerful products, and usually the most effective. They can only be issued under prescription from one of our vets (either verbal, if they are prescribing for dispensing from the clinic, or written if you want to buy elsewhere). They are legally classified POM-V (prescription-only medicine, veterinary). It is illegal to advertise the products (so we can’t include the brand names here!).
    • Most of these products are tablets containing milbemycin and praziquantel, and are capable of killing almost all worms.
    • There are also tablets containing an anti-flea component (usually afoxolaner or spinosad) and a wormer (milbemycin) to kill fleas and roundworms.
    • There is also a wide range of spot-on medications containing imidacloprid against fleas and moxidectin against worms; or selamectin against both, that are capable of killing roundworms. The combination of imidacloprid and moxidectin is even capable of killing lungworm, which is notoriously difficult to treat effectively.

With so many options, how do I decide? The best thing to do is to talk to one of our vets or nurses, who will be able to tell you which is the most suitable product for y

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