Frontline

Re: Frontline

Alex Gough — Thu, 15 Sep 2011 11:32:11 GMT

Thanks Alex, and everyone else - really useful replies which I will pass back to my vets.

cheers

alex

Re: Frontline

Alex Allen — Thu, 15 Sep 2011 10:49:22 GMT

Hi Alex,

Straight off I have to declare a conflict of interest as Virbac produces a Fipronil product - Effipro. Virbac frequently gets asked "why did you produce another fipronil product when there's widespread resistance??" often followed with stories such as the one you describe.

Answer - This decision was not a knee jerk response - market research, years of product development and testing is a huge investment and at any point if the higher powers in Virbac doubted the efficacy of such a molecule the project would have been aborted. The evidence is (to date) unable to show resistance to any if the commonly used molecules including fipronil. Anecdotal reports of resistance usually stem from inadequate treatments to animals and most importantly the environment. Stories of resistance are common from vets and owners alike but without sounding like a stuck record the understanding of the flea lifecycle is still fundamental to flea control.

Years of research has been spent looking at resistance to insecticides across a wide range of molecules but despite identifying genes they convey resistance in other insect species the flea remains susceptible to the commonly used molecules. Michael Dryden over at Kansas State has done several papers on the humble flea and has not shown true resistance with any one molecule - some of these studies were funded by companies but others are independent. If any resistance to a molecule was found then the rival companies would have had a serious party as the product sector in worth approx £60 million in the UK alone...with Fipronil products still dominating the market.

Breakdown explanations:

Incorrect Application = The breakdown of the topical spot on products does occur and the application technique is the commonest explanation (as mentioned several times above) - all of the spot on MUST be applied to the skin for optimal spread and effect. As an example if a Fipronil spot on is placed on the fur the dispersion of the product across the skin via the sebaceous secretions is slower than intended and the speed of kill may be adversely affected. In contrast Fipronil sprays work on the fur and skin surface and therefore are still considered the preferred choice for flea allergies and ticks. The entire volume of the spot on and hence dose must be used otherwise the effect will be lower than expected - this application issue lead to the design of our non-drip pipettes now being used.

Efficacy Expectations = In order to gain a market authorisation the efficacy has to be demonstrated/ proved in field trials for the claimed period. These studies may then be published in peer reviewed journals to bolster the claims made by the company. The required kill rate varies according to the insect being killed - in this case fleas and ticks. The official kill rate for fleas is 95% in 24hrs and ticks 90% in 48hrs with some species of ticks being more sensitive than others. This must be understood as in the face of a heavy infestation at the end of the claim period there may be significant fleas surviving on the animal beyond 24hrs. Fleas require >24hrs on the host to feed and then start the reproductive process. Maximal egg laying is around 4-10ds with daily egg production up to 50 eggs. Therefore historically when owners were treating every 2-3 months there may have been a few successful matings leading to the start of an infestation. Owners forget to apply at the appropriate times and it is common to hear the story of an owner that missed a couple of applications and now they have fleas crawling all over the house.

Infestations = still frequently forgotten about by vets - ALL products currently licensed mention the need for environmental control in the event of an infestation. The majority of the flea's lifecycle is off the animal and the fleas being seen on the animal a few days after applications are often recent visitors to the animal and not longstanding resistant residents. A recent example was a puppy treated and combed intensively by the owner to remove all visible fleas only to have numerous fleas again a few days later - these were not the original fleas on the animal but clear evidence of a severe infestation with fresh flea invasion. Without a household spray infestations can take months to be controlled. Another scenario is the use of product A for 2 applications but fleas are still being seen so Product B is started and within 1-2 applications the fleas disappear. The illusion of successful elimination can be assumed by Product B - BUT actually the apparent flea eradication by the second product has been due to the previous product's successful control slowly depleting the environmental numbers. Eradicating a flea infestation using just 2-3 spot-ons in a well established infestation is very unlikely without the aid of a household spray.

Owners reporting flea bites on them and seeing fleas on them are most likely to be environmental fleas recently hatched - cat fleas cannot survive off human blood and will die within 24-48hrs once biting humans. If a flea leaves the cat/dog again autolysis kicks in very swiftly and death results within 48hrs. Fleas will not generally deliberately leave the host unless it accidentally crosses over to another - ie two cats huddled together in a basket. One of the oldest tests for checking infestations was for a person to walk across a house wearing knee length white socks - the fleas were counted at the end of the walk around! Pupa hatching is triggered by a combination of warmth, humidity, CO2 and shadows. Vibrations have been suggested but the physical movement creating shadows is most likely.

Population Dynamics = unlike endoparasites in cattle / horse where resistance to drugs is a serious problem fleas have a much lower risk of selection pressure for resistance. When topical flea treatments are used only a very small percentage of the population are exposed to the insecticide reducing selection pressure considerably. Compare this to the endoparasite world where the creation of a refugia is useful to dilute the resistant worms. Add into the dynamics the fact that diffusion of fleas over vast areas is commonplace creating gene dilution. Kansas State University have deliberately engineered their KS1 flea with higher tolerances to insecticides but even that "super flea" is killed by the usual molecules.

At the end of the day it all about using a product you feel confident in and one that the owners can reliably use with the appropriate guidance and education from your practice staff.

Re: Frontline

Bob Russell — Thu, 15 Sep 2011 09:59:05 GMT

[quote user="robloxley"]

[quote user="Laurence Webb"]it may well be Bob Martins or some other ineffective treatment[/quote]

Hmmm, Bob Martin now has a treatment containing imidacloprid too...
How many people are using Advantage?

[/quote]

Occasionally we do and good it is at killing fleas. The reason we don't particularly push it (apart from it being much cheaper in Morrisons) is that it has a short life on the animal so is not particularly forgiving when the owner forgets to put it on monthly.

Strange how Bayer seem to have moved from vet only products to supplying Bob Martins. I suspect Profender will go that way soon and all these vets supplying Advocate may get a bit of a shock if this goes GSL in a few years as their other products seem to have gone!

Re: Frontline

Martin Atkinson — Thu, 15 Sep 2011 09:48:31 GMT

[quote user="newgradvet"]

I have most experience with Frontline but have used stronghold on some occassions. Surely frontline and stronghold (both spot ons) ar ethe same for ease of appliance??

[/quote]

Frontline is a much larger volume so you've got to find a larger area of skin which is obviously difficult through hair and Stronghold is more liquid so if some gets on the coat it seems to run down the hairs onto the skin more easily. Also as other posters have suggested the Stronghold pipette is much easier to open and control without spilling half of it over your fingers.

Re: Frontline

Dagmar Steele — Thu, 15 Sep 2011 07:01:01 GMT

[quote user="James Laidlaw"]

How do you squirt frontline all over your fingers? If anything, the pipette is longer and the nozzle is away from your fingers when applying... Also, if I'm being given 5 stars for my arguments, can I at least get some back up here? Feel like I'm closing a door after the horse has bolted... (reminds me of Stewart Lee's 9/11 gag for anyone that has had the fortune to see his show this year)

[/quote]

I'm dumb enough to do it when I open the pipette....

Re: Frontline

Rob Loxley — Wed, 14 Sep 2011 23:34:36 GMT

[quote user="Laurence Webb"]it may well be Bob Martins or some other ineffective treatment[/quote]

Hmmm, Bob Martin now has a treatment containing imidacloprid too...
How many people are using Advantage?

Re: Frontline

Laurence Webb — Wed, 14 Sep 2011 23:11:39 GMT

All anecdotal, but clients who have used Frontline regularly in the past are coming in more frequently reporting flea problems. Once changed to Advocate they don't come back with flea problems. As these clients found Frontline effective in the past, and now find a different spot-on treatment effective I assume they are applying the products correctly.

I tend to ignore reports from people who have bought 'Frontline' elsewhere, as it may well be Bob Martins or some other ineffective treatment or just badly applied.

Re: Frontline

Stephen Courtney — Wed, 14 Sep 2011 22:28:54 GMT

I think the reason there are no peer-reviewed articles about flea products and possible resistance is because....no one is doing the research. no one cares that much. just switch products, and life gets better. I'm talking about good, sensible, honest clients here, not liars who insist they use the product every month, and buy it from you but their clinical records show they bought a box 18 months ago. I don't think Merial will publish anything against their product, but they must know.

As for evidence based medicine vs anecdotal, it is worth remembering that evidence doesn't always constitute proof, and that anecdotes are evidence of a sort. There is evidence that people have fallen out of planes without parachutes and survived, therefore a parachute is not evidently essential to survive a skydive. Anecdotally, it's a pretty good idea though...

Re: Frontline

James Laidlaw — Wed, 14 Sep 2011 22:07:37 GMT

Re: Frontline

Claire McConnell — Wed, 14 Sep 2011 20:06:24 GMT

Ah ok. To be honest I have only ever dispensed stronghold and not used it myself so interesting to find another view. Thanks

Re: Frontline

Dagmar Steele — Wed, 14 Sep 2011 20:03:39 GMT

not for me. Stronghold and Advantage pipettes work much better for me than the Frontline type. Much easier to apply instead of squirting it all over your fingers.

Re: Frontline

Claire McConnell — Wed, 14 Sep 2011 19:58:19 GMT

[quote user="Martin Atkinson"]Whether this is purely poor compliance because it is so difficult to apply effectively or if its just crap I don't know.[/quote]

I have most experience with Frontline but have used stronghold on some occassions. Surely frontline and stronghold (both spot ons) ar ethe same for ease of appliance??

Re: Frontline

Martin Atkinson — Wed, 14 Sep 2011 19:24:56 GMT

Had a flea ridden cat today whose owner initially said she used 'Spot On' from the pet shop. After the usual temptation to bang my head on the wall as a demonstration of its effectiveness her daughter who is a veterinary nurse phoned and told me that her mum was using Frontline from the practice she worked in. I reiterate: in my experience Frontline has never been as effective as Stronghold so it is nothing new. Whether this is purely poor compliance because it is so difficult to apply effectively or if its just crap I don't know.

Re: Frontline

Bob Russell — Wed, 14 Sep 2011 15:34:43 GMT

I have discussed this failure with Merial Reps. I was discussing it with one rep in the waiting room, he presented the data / proof that there was no resistance problem and in the few minutes this was going on we had two people (good clients) come in requesting something 'stronger' because Frontline was not working.

I understand that for a drugs company to even mention 'resistance' in a competitors product they need proof and it is apparently very difficult to prove resistance not least because you have to grow fleas on for generations and prove product failure.

Is there proof that fleas are permethrin resistant? We all know that these products are bordering on a waste of time for flea control.

I suspect other companies are quite happy to sit back while the failures of Frontline (and clones) steadily destroy the product reputation. I still stand by my belief that the stuff is far less effective than it was and other products can make fleas invisible to the owner within a couple of treatments.

Re: Frontline

James Laidlaw — Wed, 14 Sep 2011 13:50:31 GMT

Surely if so many people don't think it works to the point they use a different product and claim that THAT SOLE CHANGE has made the difference from a treatment working to a treatment not working, there should be some research into this or some trials showing this is the case?

Pardon me for playing devils (Merial's?) advocate, but I prefer concrete facts over anecdotes, be they true or otherwise.

Is anyone anywhere looking into these claims? Are vets reporting these failures to Merial?

As I said, I haven't had any problems yet, but am surprised to constantly hear of vets who have, and clients coming in who have heard of vets saying the same to them, when there is no concrete information present to advise as such...

Re: Frontline

Martin Atkinson — Wed, 14 Sep 2011 09:30:17 GMT

This is an old chestnut, there is another thread on the same subject. IME Frontline spot-on never worked very well, certainly not for 5 weeks for cats as claimed, IMO its a combination of being difficult to apply, so lack of operator compliance, and cats especially licking it off. As suggested the spray knocks fleas down within minutes so resistance is unlikely unless that's just the exipient making them pissed! We have for years recommended Stronghold and more recently Advocate. I washed my hands of Frontline when it went GSL and Merial cynically brought out Combo, unless someone has a tick problem.

Re: Frontline

Bob Russell — Wed, 14 Sep 2011 09:21:32 GMT

Nope I think it is failing. I am not sure this is full resistance as the spray still seems to knock the out! I wonder whether the effective killing dose is now insufficient especially for cats.

We have had many cases where owners have been fully compliant and the flea problem has got out of hand. Many comply poorly but I doubt this has changed in any way. It used to work well, now does not.

Resistant? Not sure but failing definitely IMO.

Re: Frontline

Dagmar Steele — Wed, 14 Sep 2011 09:09:56 GMT

I have, as I have seen many cats with a lot of living fleas on them one week after application. Most of the owners were intelligent and responsible enough to use the product as they should and I've questioned them about it. I have also seen many families struggle with flea problems on Frontline for ages, once they swapped to Advantage (Imidacloprid) the problem could be solved.

There have been numerous cases like this and it's been too many that I can be convinced that the product still works as it should, especially as other products solve problems that Frontline can't get rid of. I have not been selling it for some years now, although I must admit the spray is great when you want to get rid of ants :-)

Re: Frontline

James Laidlaw — Wed, 14 Sep 2011 08:52:30 GMT

This topic comes up a lot I think - but I would have thought if resistance truly existed, we'd have seen something in peer reviewed papers? In my experience there is always a flaw somewhere in the treatment plan or environmental control. Frontline doesn't stop fleas jumping onto the animal either. I'd be interested to see if anyone has filed any reports of treatment failure that remain unexplained to Merial though.