Max Metacam dose for short-term use?

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TWP_2

Post   » Fri Dec 01, 2006 4:56 pm


Our Metacam is 1.5 mg/ml. Gilbert's current maximum dose is 1.3 ml (1.95 mg).

The information I've found online lists canine limits as 0.2 mg/kg, avian as 0.5 mg/kg, and rats at 1.0 mg/kg.

Jim

(This post was actually supposed to post about three up ^^^ but I forgot to hit "submit"!)

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Mum
I GAVE, dammit!

Post   » Fri Dec 01, 2006 5:05 pm


I would check with other people. Perhaps Josephine?

This is contrary to everything I know, and I'd really like to have this verified.

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Sef
I dissent.

Post   » Fri Dec 01, 2006 7:00 pm


Wrong, wrong, wrong. Your vet is using the rodent dosing guidelines for Metacam in the Formulary, which, according to an email that Mr. Carpenter himself sent me (after my former vet over-dosed the drug by 10x, and my discussions with the Formulary's publisher left us both puzzled about the major discrepancy), is based loosely on his expert's opinion of how rats metabolize the drug. While it's not a typo per se, your vet should notice that guinea pigs are specifically not listed under that drug in the rodent section.

The dosage for guinea pig needs to be based on the recommendation in the rabbit section of the book, which is .1-.2mg/kg.

EDIT TO ADD: This information was also backed up by Boehringer Ingelheim, the drug's manufacturer.

User avatar
Lynx
Celebrate!!!

Post   » Fri Dec 01, 2006 7:45 pm


Ah, it was you, sef? I didn't remember who. I see I got some of the details mixed up. All I knew is it was wrong. I was going to recommend having them contact the manufacturer too.

Talishan
You can quote me

Post   » Fri Dec 01, 2006 8:24 pm


We went up to .45 mg/kg twice a day (for a total of 0.9 mg, he weighed about a kilo at the time) one time, for one day, for our dental pig:

https://www.guinealynx.info/forums/viewt ... p?p=387854

He didn't have any trouble with it and it helped him. I wouldn't go anywhere near that high for very long, though.

For more 'regular' use, even on a short-term basis, we've had success giving a little more than one-half the standard dose twice a day, rather than the full standard dose once a day. I think the highest we've used other than the exception above was 0.2 cc's, or 0.3 mg/kg for a one-kilo pig, twice a day. That was for a day or two only in each case.

TwoWhitePiggies

Post   » Fri Dec 01, 2006 9:32 pm


Here's the e-mail that came back from our vet, Dr. Swenson, at K-State:

Diana,
Yes, this frequently confuses people (and vets) who look through Carpenter's formulary (this is the primary drug reference used for exotics, and happens to be edited by none other than our Dr. Carpenter, the head of the zoo service here at K-state). I asked Carpenter about this when I first noticed the discrepancy. In every other species of animal besides rodents, Metacam is listed at 0.1-0.2 mg/kg (since metacam is 1.5 mg/ml, this works out to be 0.06 ml to 0.13 ml for a 1 kg pig). However, in rodents, it has been tested at a dose range of 1 - 2 mg/kg. IN RODENTS ONLY! This is what is listed in Carpenter's formulary. It is NOT a typo and it will not be changed in future publications as it has solid evidence behind it to support it. It is confusing since all other species are listed at 0.1-0.2 mg/kg. This is mostly because the studies at these high doses haven't been done yet in species other than rodents.

So, don't worry, this is not a massive overdose. In a rabbit, it could be, but guinea pigs tolerate metacam very well. Now one thing that I should clarify in what you said was that GPs can get up to 2 mg per kg of body weight, not 2 ml per kg. At the 1.5 mg/ml concentration, this means that for a 1 kg GP (like Gilbert) the dose range is from 0.7 - 1.4 mls of metacam in a 24 hour period (hence why Gilbert is up at 1.3 ml).

Feel free to add this to the list. Every situation is unique, and when
starting pigs on metacam, we typically start at a dose of 0.3-0.4 mg/kg just to be safe. However, I have quite a few rodents now on much higher doses, such as what Gilbert is on with no side effects. Rodents seem to tolerate the drug quite well and don't have the same sensitivity to the GI side effect that other species do. Having said that, I don't recommend anyone playing around with the doses of any drugs without consulting their veterinarian, but I think it's important to clarify that the listing in the formulary is NOT a typo.

User avatar
Sef
I dissent.

Post   » Fri Dec 01, 2006 10:17 pm


I wonder if I kept my email from earlier this year. Dr. Carpenter had forwarded my question on to his source in the UK -- the person who had done experiments on lab rats and mice, and had made the determination that a dose of 1-2mg/kg was most effective for their faster metabolism. Carpenter's listing in the rodent section is based on this individual's personal recommendation, but Carpenter himself was a little vague as to whether or not he felt it should be applied to guinea pigs. If you look at the Formulary in the Rodent section, there is no listing for guinea pig under Metacam -- it says "rats/mice." With other drugs, it specifically states the dosage for guinea pigs where applicable.

Technically, no -- it's not a typo. But it's not very clear, either.

What was the most convincing for me, though, was my discussion with a rep from Boehringer. When I initially told this person that my vet had prescribed Metacam at 1-2mg/kg, the rep (I probably still have her name at work, if anybody wants to contact her directly) stated that this was "unusually high." She went on to say that their 'unofficial' recommendation for off-label use (since Metacam for guinea pigs is considered off-label) is roughly 1 drop per pound. She said that many vets don't bother to actually calculate this out for smaller animals, since it's such a small amount. Obviously, 2ml of Metacam is not a small amount. The rep also faxed me the information that they refer vets and other individuals to when they inquire about administering Metacam for guinea pigs. It's the rabbit section of Carpenter's Formulary -- not the rodent section. This is when I decided to buy the book and see for myself.

I'm no vet and I'm certainly no expert in this drug, but based on Carpenter's explanation, I tend to go with the manufacturer on this one and err on the side of caution.

User avatar
TWP_2

Post   » Fri Dec 01, 2006 10:24 pm


Interesting that the rep would direct you to a guide for lagomorphs, and not for rodents. I wonder why?

User avatar
Mum
I GAVE, dammit!

Post   » Fri Dec 01, 2006 10:36 pm


a rep from Boehringer. When I initially told this person that my vet had prescribed Metacam at 1-2mg/kg, the rep (I probably still have her name at work, if anybody wants to contact her directly) stated that this was "unusually high." She went on to say that their 'unofficial' recommendation for off-label use (since Metacam for guinea pigs is considered off-label) is roughly 1 drop per pound
Hmmm, I would think the company that makes it would know?

Talishan
You can quote me

Post   » Fri Dec 01, 2006 11:00 pm


"...would direct you to a guide for lagomorphs, and not for rodents. I wonder why?"

Because a guinea pig is not a rodent. They're not lagomorphs, either, they are caviomorphs, but they are much closer (at least in digestive, and I would speculate metabolic, function) to a rabbit than a rat.

"Hmmm, I would think the company that makes it would know?"

They have a good idea, and, like Sef, I would tend to trust them, although the one drop per pound sounds ineffectively low. They can't legally say. It is time-consuming and very expensive for drug makers to do the testing that gets drugs approved for veterinary use in species x for condition y. The dog-cat market is big enough to justify the time, expense and effort. The small mammal market isn't, yet, anyway, hence 'off-label' use. But they know that vets know that this stuff works, so while manufacturers can't legally commit to a product or dose for a condition, they can make unofficial recommendations as to what they know, from their own research and/or from what veterinarians using their product have reported back to them.

TwoWhitePiggies

Post   » Sat Dec 02, 2006 3:07 am


They have a good idea, and, like Sef, I would tend to trust them, although the one drop per pound sounds ineffectively low. They can't legally say. It is time-consuming and very expensive for drug makers to do the testing that gets drugs approved for veterinary use in species x for condition y.

Everything that I could find on the metacam site showed that the drug was originally approved for dogs, and has just now officially been approved for cats in the U.S., and I'm thinking a few other animals in a few other countries. But nothing official for guinea pigs.

TwoWhitePiggies

Post   » Sat Dec 02, 2006 3:11 am


Just as a note, when I looked up caviomorphs:

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Suborder: Hystricomorpha
Infraorder: Hystricognathi
Parvorder: Caviomorpha

And when I looked up lagomorphs, it showed this:

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Lagomorpha

Doesn't this mean that their common ancestry is the mammal? I once made a comment about guinea pigs being in the same family as rabbits to a biology professor, and he told me that humans had as much in common with whales as cavies had with rabbits.

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