Ease of administering the dose
Wormers come in various forms - ask your vet for advice about products that could make worming your pet easier and more enjoyable.
Which parasites will a given treatment cover?
It’s also worth talking to your vet about the types of worm each product covers – for the best level of protection they will probably recommend one that they need to prescribe – these ‘vet strength’ products cover the broadest range of parasites.
Need for isolation period
Some spot on wormers state that you need to keep your pet away from other pets or family members immediately after giving the dose to prevent the liquid contacting humans and causing problems.
Minimum ages for puppies and kittens
Some wormers are suitable for puppies from 2 weeks and kittens from 6 weeks. Talk to your vet about the most appropriate wormer in young pets.
Suitable for all?
If you are looking to treat a breeding dog, pregnant or lactating bitch/queen do mention the circumstances since not all worming treatments are appropriate.