Hmmm, I would think the company that makes it would know?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
- I GAVE, dammit!
- You can quote me
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.
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.
And when I looked up lagomorphs, it showed this:
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.
I'll probably be going in to work sometime this weekend (joy)...I'll see if I kept the emails that were being passed around about this between Dr. Carpenter and Elsevier Saunders back in January. I'm having trouble remembering exactly what Carpenter's UK source said about guinea pigs.
- I GAVE, dammit!
She basically said what TWP said, that GP's metabolize the stuff quickly.
I've always preferred giving 2 half doses every 12 hours rather than 1 dose per 24 hours.
I have absolutely nothing to base this on except my own personal experience with pain and pain meds.
I know I'm not a guinea pig, but with my meds, I get much better pain relief with dosing smaller and more frequently than dosing once per day.
When I was giving Zachary Metacam for his bladder inflammation, I gave 2 doses of .1 every 12 hours and it seemed to be very effective in giving him some relief.
This is an interesting discussion!
--------------------------------------------------...I contacted the manufacturer of Metacam, Boehringer Ingelheim, and spoke to one of their representatives about off-label use of the drug. While they are unable to make specific dosing recommendations for guinea pigs, they referred me to the rabbit dosing information in your book -- stating "hypothetically" that .1-.2mg/kg would be an appropriate dosage for guinea pigs as well.
Based on this information, I suspect that the 1-2mg/kg reference [in the rodent section] is a typographical error made by Elsevier Saunders, but I wanted to contact you directly and ask for clarification. Ms. Rudolph indicated that plans are already underway to change the rodent reference in the 4th edition, but she has been unable to confirm to my satisfaction that this was indeed an error and not a recommendation that you may have made.
Any help you can give me into this matter would be greatly appreciated.
---------------------------------------------------Dear Ms. F:
(I'm resending this email with the attachment.)
The meloxicam dose we cited in the Formulary is higher than we generally use, but according to the researcher in England, it is correct. Please see the attached citation.
Best wishes. Dr. Carpenter
>Greetings from Kansas. As author/editor of the "Exotic Animal
>Formulary", I've had a number of inquiries regarding the
>meloxicam dose our book. We based the rodent dose of 1-2
>mg/kg on the Vet Clinic of North America: Exotic Practice (your
>citation). The VCNA has a number of your references pertaining
>to analgesics; can you let me know which one(s) contain the
>research (or the recommendation) for the 1-2 mg/kg of
>meloxicam in mice and rats (recommendations for rabbits and
>most other small mammals are 0.1-0.3 mg/kg)? Also, do you still
>feel comfortable with this dose, and is it the one you are still
>recommending (and have seen no adverse effects?)?
> James W,. Carpenter, MS, DVM, Dipl. ACZM
> Professor, Zoological Medicine
> Kansas State University
Following is our reference for the meloxicam dose in rodents.
ROUGHAN, J.V. and FLECKNELL, P.A. (2003) Evaluation of a short-
duration behaviour-based post-operative pain scoring system in rats.
European Journal of Pain, 7, 397-406 has the rat data; the mouse recommendation is based on clinical impression (and cited in Pain Management in Animals), but we should be publishing much more detailed dose rates later this year once Sian completes her PhD. Both species dose rates are what we still use, and we've seen no adverse effects.
Prof. Paul Flecknell
Comparative Biology Centre
Medical School, Framlington Place
Newcastle, NE2 4HH
0191-222-6715 (Voice) 0191-222-8688 (Fax)
view our educational resources at: www.digires.co.uk and www.ahwla.org.uk
Flecknell doesn't say that this dose should also be applied to guinea pigs; he says it's correct for "both species" (rats and mice). Maybe my interpretation is off, but I really don't see anything in either his or Dr. Carpenter's comments that make me think 1-2mg/kg also applies to guinea pigs -- especially since Carpenter made the comment, "...recommendations for rabbits and most other small mammals are 0.1-0.3 mg/kg."
While you can't go tragically wrong with lower doses, I don't read in that exchange any last word that would remove GPs from the rodent dose category. I can vouch for the effectiveness of high dose Metacam in making Gilbert more comfortable in his last few months.
- I Love Lucy
Gilbert's necropsy report showed no changes that were attributable to the high dose Metacam. They did find some mild liver abnormalities, but they attributed this to effects from the stone problems and not to Metacam.