Sis Deserves A Beatdown

[nonseq]

My sympathies on the lice infestation. DD brought the little suckers home from camp one year. It was awful to get rid of them.

 

[cmjust0]

Quote:
You do realize that 'topical' applications of products like Frontline don't act topically against parasites, right? They're specifically designed to soak into the skin and go directly into the bloodstream, where they kill the parasite as the parasite consumes the host's blood... That's how they work. As you were dripping it onto your kiddo's head, you were literally putting the contents of a frontline packet directly into her bloodstream.

 

[Orchid]

Quote:
You do realize that 'topical' applications of products like Frontline don't act topically against parasites, right? They're specifically designed to soak into the skin and go directly into the bloodstream, where they kill the parasite as the parasite consumes the host's blood... That's how they work. As you were dripping it onto your kiddo's head, you were literally putting the contents of a frontline packet directly into her bloodstream.

Actually...

FRONTLINE Top Spot and Plus spread over the pet's body by a process called translocation. When applied, these products are gradually dispersed by the pet's natural oils, collecting in the oil glands in the skin. It is then "wicked" onto the hair over the next 30 days. The translocation process can take up to 24 hours to complete.

Not that I'm advocating using Frontline on your kids, because I'm not.​

 

[cmjust0]

Quote:
Not that I'm advocating using Frontline on your kids, because I'm not.

Well...

• Pharmacokinetic properties:
Metabolism studies have shown that the fipronil was transformed mainly into its sulfone derivative. The (S)-
methoprene is extensively degraded into carbon dioxide and acetate which are then incorporated into
endogenous substances. The pharmacokinetics after topical administration of fipronil and (S)-methoprene in
association have been studied in cats in comparison with those of each active ingredient administered
separately intravenously. This allowed to estimate the absorption and other parameters pharmacokinetics under
conditions of use.
In cats, after administration of the association topically with oral exposure potential by licking, fipronil has an
absolute bioavailability (18%) with a mean plasma concentration Maximum of approximately 100 ng / ml for
fipronil and 13 ng / ml for fipronil sulfone.
In dogs after administration of the association topically, fipronil is poorly absorbed (11%) with aaverage
maximum plasma concentration of approximately 35 ng / ml for fipronil and 55 ng / mlfor fipronil sulfone.
In cats, the plasma concentrations of fipronil rapidly reach a peak average of about 6 hours and decreases with
a half-life by approximately 25 hours.
In dogs, the plasma fipronil concentrations slowly reached a peak average about 101 hours and decreasing
slowly (half-life) by approximately 154 hours, the highest values are observed in males.
Fipronil is poorly metabolized by fipronil sulfone in cats.
Fipronil is extensively metabolized by fipronil sulfone after topical administration.
Plasma concentrations of (S)-methoprene are generally below the quantification (20 ng / ml) in cats and dogs
after topical administration.
Fipronil and its main metabolite and the (S)-methoprene spread widely in the cat's coat the day after
application. The concentrations of fipronil, fipronil sulfone and (S)-methoprene in peeling decreases with time,
but are detectable at least 59 days after application in cats and 60 days after application in dogs.
Parasites are killed mainly by contact and not by systemic exposure.
No pharmacological interference between fipronil and (S)-methoprene was detected.

Note the mention of "plasma concentrations" -- that's blood.

What I'd always thought happened was that the med circulated in the blood and that the parasite was killed by consuming the blood, as is the case with most "pour-on" antiparasitic medications ("Iver-On" pour-on ivermectin, for instance)... I was clearly wrong about that, though...the doc states that it kills "mainly by contact." So, fair enough on that point..

However...the "translocation" process, according to the pharmacokinetic profile, seems to occur as a result of the meds' routes of elimination being through skin oils. Meaning, of course, that it's taken into the bloodstream, metabolized, then excreted through oil glands, whereas some medications are eliminated through urine, feces, milk, etc....

I found that document here (though it's a ginormous, dynamic looking hyperlink that I'm not sure will work right...if not, google 'frontline pharmacokinetic properties' and it'll be right up near the top as a PDF entitled "Frontline Combo".)

FWIW, same document also lists precautions for administration:

Special precautions for person administering the medication:
This product may cause irritation of mucous membranes, skin and eyes. So avoid contact of the Product with
the mouth, skin or eyes. Animals or those who have known hypersensitivity to insecticides or alcohol should
avoid contact with the drug. Avoid contact of contents with the fingers. If this occurs, wash hands with soap and
water.
In case of accidental exposure with eyes, rinse with clean water carefully.
Wash hands after application.
Do not handle animals treated and not allow children to play with treated animals until that the application site is
dry. It is therefore recommended that animals are not treated in the day but in the early evening and that
recently treated animals are not allowed to sleep with owners, especially children.

The last bit of emphasis is mine.

 

[Orchid]

It did mention

after administration of the association topically with oral exposure potential by licking

, which would definitely introduce the product into the bloodstream.

Either way, spread via bloodstream or via the sebaceous system, I am with you, I would never put this stuff on my kids.

JMHO​

 

[cmjust0]

Quote:
, which would definitely introduce the product into the bloodstream.

In cats, yes...but no mention of that was made in regard to dogs. Where dogs are concerned, it simply says it's "poorly absorbed" but reaches a plasma concentration level of blobbity blah blah via topical administration.

Which, of course, means it's going into the bloodstream from the skin.

Either way, spread via bloodstream or via the sebaceous system, I am with you, I would never put this stuff on my kids.

JMHO

Yeppers.. I'm not opposed to using things waaaaaaaay off label IN MY ANIMALS, but in human kids?.. Uh, no.

On a related note, did you know that different parts of human skin have different rates of absorption (or, varying degrees of resistance to absorption, depending on how you look at it)? The hands?...not much absorption. Bottom of feet?...about the same as the hands. Scalp?...about 3x more absorbant than the hands or feet!

I'm sure it's the same with dogs, which is why THEY TELL YOU SPECIFICALY WHERE TO APPLY THE MEDICATION. I'm sure some attention has been paid to how well things absorb along that specific location -- along the topline of the back, that is -- in dogs..

And that doesn't take into account the fact that human beings -- largely hairless as we are -- have an incredibly complex vascular system in our skin which helps us with cooling.. We send blood to the surface of the skin to diffuse heat, whereas dogs pant...totally different architecture!

And none of that even takes into account the fact that we have no clue how this stuff acts in humans.. Dogs have a much, much faster metabolism than humans, afterall. If a dog still has detectable levels of this stuff after 60 days, who knows how long it would take a human to clear it..

Scary.

 

[Orchid]

I did know that about absorption rates on different parts of the body - cheeks, for instance, are super absorbent, as are underarms and genitalia. Bottom cheeks - not so much.

That's why you hardly ever (not never, but hardly ever!) get poison ivy, for instance, on the palms of your hands - the skin is just too thick.

The other problem (IMO) with using pet medications in people is that pets naturally have a much shorter life span than people do, so they have less time for substances to build up in their bodies, and less time to be affected by the substances with which they do come into contact.

 

[cmjust0]

Ya know what's weird is that when they make those comparisons between different body parts, the baseline is the forearm.. That's a 1.0... The palms of the hand are like 1.3 and the scalp's like 3.7 or something like that, which would indicate that your palms are *more* absorbent than your forearms.

When you mentioned poison ivy, I had to laugh because when I first saw the absorption chart I kinda went "Soooooo, how come I always get poison ivy on my forearms -- but never on my palms!!??"

 

[Orchid]

Quote:
That is kind of bizarre isn't it?

Maybe we just tend to wash our hands more often than our forearms? Well, I hope so, anyway!

 

[babylady4]

The severity of a rash from Poison Ivy depends on how long the Urushiol oil sits on your skin and how your body reacts. We tend to use our hands a lot and wash them a lot so it make sense you would not likely get a rash there. That being said I have had Poison Ivy in-between my fingers and onto my palms.

Just an FYI.