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Flea medicine vs collars: How to find out which is right for you

Flea medicine treatment
(Image credit: Getty Images)

Fleas are one of the downsides to our fluffy friends, but luckily they are easily prevented by using flea medicine or collars. If you’ve ever stepped into a pet store and been alarmed at the range of options available to you, you’re not alone. 

A quick search of shows over 250 different flea products available, from spot-on medications, to flea medicine tablets, to the best flea treatment for dogs and the best flea treatment for cats. How are you supposed to know which is best? Let’s get stuck in and help you figure it out.

(Image credit: Getty Images)

Flea medicine overview

Flea medicine can come in several forms. Spot-on liquids are a very common form of flea medicine, but flea tablets are becoming more common. They work in a variety of ways and contain a variety of different active ingredients. Some are prescription-only, and others can be bought over the counter. 

Flea medications work in different ways, but in all cases the active ingredient is a drug that is more toxic to insects than it is to mammals. The drug gets spread around the body by the skin oils or the blood steam, then poisons any insects that feed on your pet.

The case for flea medicine

Giving flea medicine to your pet is a  reliable way of preventing a flea infestation. The medications can last from one to three months, providing long-lasting and continual protection. They’re usually easy to give – the spot-on medications simply get applied to the skin where your pet cannot lick them off, and even the tablets are flavoured and chewy to encourage pets to eat them. 

Many flea medications are also effective against other pet parasites, like ticks, mites and lice. They are usually very fast acting, with some formulations acting within just 30 minutes to treat all adult fleas living on the pet.

The case against flea medicine

Flea medicines are chemicals that are toxic to fleas. Unfortunately, this means they’re probably toxic to all insects; bees and other beneficial insects included. Whilst we’re yet to find out if the newer tablet-style treatments cause problems, imidacloprid is a common ingredient in spot-on treatments that is known to have serious and long-lasting effects on insects. And when your dog rolls in the grass or goes for a swim, it’s possible the medication will enter the environment and damage our wildlife. 

In addition, flea medicines can all have side effects. Whilst these are usually rare and mild, there are breeds and certain dogs that shouldn’t have some medications. 

This is why the best flea medications are only available from the vet, or with a written prescription from a vet – they’re best placed to make sure your flea medicine is as safe as possible. However, this tends to make them more expensive than simple shop-bought supplies. 

Flea medicine: The verdict

Flea medicine remains an effective way to prevent these parasites from choosing your pet as their favorite fodder. However, the most effective products are only available from the vet who will need to conduct – at a minimum – an annual evaluation to check that the product is the best one for your pet. The great news is that, no matter your pet’s individual needs, there will be a medication out there to help them.

(Image credit: Getty Images)

Flea collar overview

Flea collars are another method of flea prevention. Some collars contain a repellent, designed to stop fleas from attaching to your pet and coming into the house. Others contain a combination repellent and pesticide, which rubs into the skin on your pet’s neck and then acts in the same way as a spot-on medication. 

The case for flea collars

Flea collars are long-lasting and easy to apply to most pets. They can be one of the cheaper flea treatment options out there, depending on the brand and frequency with which you should apply it. 

Some flea collars are specifically recommended for certain insects, as the repellent action prevents insects from biting, and therefore stops them from transmitting diseases to your pet. 

The case against flea collars

Most vets will agree that the vast majority of flea collars in the supermarket aren’t effective, but there are a couple of brands that are. 

Flea repellent collars are rarely strong enough to do a good job, and fleas can easily hitch a ride with your pet, then go dormant until the collar starts to run out. 

If you have a large pet, this is particularly true, as the repellent may not be enough to keep fleas away from their back end. 

It’s also important to think about collar safety – cat collars should not be stretchy, but should instead have a quick-release feature that causes the collar to snap if too much pressure is put on it. This means that if cats become stuck, the collar snaps to release them. 

This safety-feature is life-saving, but does mean that collars get left behind and frequently lost, so their protection is sometimes limited: collars need to be worn continually to work. 

Although they can get wet in the rain, prolonged wetness or frequent bathing should be avoided for most collars, making them a poor option for dogs that like to swim or need regular grooming. 

Seresto Collar

A non-prescription flea and tick collar that repels and kills adult fleas and ticks.

Flea collars: The verdict

Flea collars are usually less effective than medications, but there are exceptions. And whilst some of the most effective flea collars remain prescription-only, Seresto has recently been recategorized as a POM-VPS product, which means you can buy it from other qualified people such as in a pet shop or pharmacies. Take care to purchase from reputable companies though; there have been lots of reports of ineffective fakes since Seresto was downgraded to POM-VPS.

Dr Joanna Woodnutt MRCVS

Dr Joanna Woodnutt is an experienced vet with an interest in companion animals. She recently left full-time practice to work as a relief vet and write articles about pets.