Sunday, June 24, 2012

New Pain Medication for Cats

Now this is interesting.. I just learned there is a new "three day" pill for cats called Onsior (robenacoxib)  (got to love these names for medications!!)

You give one pill once a day for three days.  It is especially formulated for cats and has safety studies for up to six months. which to me could imply that you can give it for six months, but in other areas of the page it says for up to three days, or three days of pain relief for cats, so I'm assuming there is going to be some confusion here and possibly that some vets might prescribe it for longer then three days... lets hope not.

Since the problems with Metacam and Convenia, I'm very leery of new pain medications for cats. so I went to their website.  On the how does it work page, I find some  information that makes me pause.  On one hand it says it is eliminated quickly from the blood (Mean blood t1/2 of 1.7 hours) but it then says it has demonstrated tissue selectivity (clinical significance unknown) and apparently hangs out where it is necessary.  so then how is it cleared from the body after this?  and if it is cleared from the blood, how do you know it has cleared from the tissue in question

 Also on the "how does it work" page, there is the impressive results of the fact that it has an 83.5% success in the field study (n=164)  but when you realize that the placebo had a success rate of 53.8% (n=80) why isn't the groups the same?? it appears that it only has a 30% improvement over nothing.

On the safety data and field studies page I found this..
Onsior safety studies for up to six months.  The Onsior clinical trial field along with the 6-month safety study, support the safe use for 3 days. (and) There was no clinically significant difference between groups for hematology, serum chemistry, or urinalysis results.
Which goes on to say
 Robenacoxib was well tolerated when administered at 24 mg/kg/day for 21 days, except for 2 cats that experienced neurologic signs. 24 mg/kg/day is the equivalent of giving an 11 lb cat 20 tablets per day.
there were eight cats in this particular study.  So if your cat is overdosed then you have a 25% chance of your kitty having neurological issues.  I guess the chance of you giving your cat 20 pills a day - when the standard is one -  is kinda low, but this stat still scares me.

I am bothered by the extremely low numbers that this has been tested on.  I won't be giving any of this to any of my cats until it has been out for quite some time and we can get a better handle on the side effects that might not have been seen in smaller studies.  There are so few options for pain management in cats that it nice that they are coming out with additional options and I do support that.  It is just sad that some kitties will end up paying the price for it.


  1. There's a Metacam supply problem in the US too? I thought it was some distributor issue in our country...

  2. I'm not aware of a supply issue in the US for Metacam (there is for terramycin though) But there can be a problem medically giving it to cats. Many have had very severe complications after being given Metacam.

    I did give it to Ollie when he was dealing with his vaccine associated sarcoma since I knew he was in some manageable pain and that his life was ending sooner rather then later. It was very helpful to him since his incision was right near his leg.

  3. It is sad and frustrating how few pain medications are available for cats. Thanks for the information.


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