Are Fleas Resistant to Frontline? Why is Frontline Not Working?

Frontline Resistance

A lot of people find fleas on their dogs or cats even though they are using Frontline Spot-on or Frontline Combo. Sometimes this is after several years of perfectly successful use. The obvious conclusion is to think that the Frontline is not working. In a way this is true. However, this is because the expectation was unrealistic, not because fleas have become resistant to Frontline. Whenever cases like this are investigated, it turns out that the Frontline is killing the fleas, but something else has gone wrong. Genuine resistance is talked about, often by vets too, but is not the cause. Almost always there is another explanation, and the Frontline will work fine again once the build-up is brought under control. Simply applying Frontline periodically will usually work perfectly well, but if other conditions suit the fleas, they will have the chance to get going. Once they have become established, it takes a concerted effort and quite a period of time to eradicate them. It is always best to use Frontline every month throughout the year. Anything less than this will sometimes lead to problems.

To Buy Frontline, click here

Frontline controls fleas;

and Frontline controls ticks;

but depending on conditions,

you may need to do more...

The Difference between Frontline Spot-on and Frontline Combo

There is very little practical difference between the two products. Forgive me for being cynical, but Frontline Combo was brought out as a product when the older Frontline Spot-on was moved into a different legal category. Before this happened, only Vets could sell Frontline Spot-on as it needed a prescription. Vets were therefore the manufacturer's main selling tool for Frontline Spot-on. As soon as the manufacturer lost this position, they brought out a new Vet-only, prescription form of Frontline - Frontline Combo. It is true that the additional ingredient in combo (s-methoprene) means that if you fail to apply the next dose as soon as you should, the methoprene will in effect sterilise the female fleas living on that animal for a while. However if you apply Frontline at the correct intervals, there is no effective difference between them. They both kill fleas in exactly the same way.

Why can I still see fleas after using Frontline?

By the time you see any fleas, there are normally lots around. They are extremely good at hiding out of sight, they have been practising this for millions of years and are pretty good at it! Every female flea on your cat or dog will be laying eggs, which drop to the ground. Here they gradually develop into larvae, pupae, then adult fleas. Then they look for something warm and tasty to get a meal from. Your passing dog or cat is ideal, but even you might do if they get really hungry!

It is often said that there are 100 fleas in the house (lots of them are still eggs) for every one adult on your pet. As these fleas develop and need to feed, they seek out your pets and jump on them. If this happens a couple of weeks after you have applied Frontline, you might see them and think the Frontline is not working. In fact those fleas will probably die soon. Actually they are particularly easy to see when the Frontline is taking effect, so it looks worse than it is. However they will soon drop off and die, only to be replaced by more fleas from the carpet or wherever. This can continue to happen for months sometimes. Every flea jumping onto your pet might be dead after about 24 hours, but if there are enough developing in the environment, you will continue to see new fleas on your pet all the time. Hence the fleas seem to attack in waves, coming from an endless reservoir which built up before you even new there were any fleas around.

So how do I get rid of fleas?

You need to apply the Frontline (or other effective product) correctly. It needs to come into contact with the skin, so you need to part the hair on the back of the neck and slowly tip it on. Make sure none rolls off the hair onto the ground. Make sure the Frontline is not rubbed, licked or washed off for a few hours. Do treat all dogs and cats, not just the "worst" ones.
Get rid of as many fleas from the environment as you can. Pet bedding needs to go through a hot wash (60 degrees C). All floors should be vacuumed (including underneath all furniture if possible). This will collect a lot of fleas and eggs etc. It will also stimulate dormant fleas to develop, rather than stay in the nooks and crannies for ages. (Vibration and warmth encourages their development.)
Spray around all the floor areas of the house with a good insecticide. "Acclaim" or "RIP Fleas" are good products. This is important even in areas with no carpets. Flea larvae are happy in the cracks between floor boards, or any other little crevices.
Continue to re-apply the Frontline every month, and vacuum the floors weekly.
In future use Frontline before you see any fleas. It works stunningly well as a preventative, but only slowly at removing an established flea population. That means using it all year round ideally, on every pet.

VioVet is an online retailer of just about everything for your pet:

Prescription medicine (you need a written prescription from your vet). Often about half price for just the same product, from the same UK wholesalers, as used by your own vet.
Non-prescription medication. You can buy Frontline Spot-on without a veterinary prescription. Frontline Combo needs a prescription however.
A huge range of literally hundreds of diets, from premium quality to budget. You name it, we probably sell it!
Thousands of pet care products, from dog collars to fish tanks. All available on one website at the lowest possible prices.

Article written by:
John Cousins BVSc MRCVS - A veterinary surgeon from VioVet - Online Pet Store & Pharmacy.

The article reflects the opinions of the author and should only be used as a guide. It can only be taken in conjunction with advice from your vet. No liability is accepted for accuracy of content or any other matter.