suki & crystal (GA)
Very Active Member
So lovely to hear that Chris is having good days
a very handsome boy too!

Ondansetron comes in 4mg pills, and a commonly used dose on Tanya's Support Group is 1 mg each day, so one pill contains four doses.
This seems to work well for many CKD cats; however, Pet Place mentions that the usual dose for cats is 0.11mg per pound bodyweight every 8-12 hours, i.e. 1.1mg for a 10 lb (4.5kg) cat given 2-3 times a day. Plumb's Veterinary Drug Handbook mentions an empiric dose of 0.5mg per kg bodyweight twice daily, so a 10 lb (4.5kg) cat would be given 2.25mg twice a day.
Oral, subcutaneous and intravenous pharmacokinetics of ondansetron in healthy cats (2014) Quimby JM, Lake RC, Hansen RJ, Lunghofer PJ & Gustafson DL Journal of Veterinary Pharmacology and Therapeutics 37(4) pp348–353 found that subcutaneous administration was more effective then oral dosing. It also states "twice daily administration at 0.5 mg/kg is likely inadequate to maintain serum concentrations within the therapeutic range; higher or more frequent doses may be needed." However, it further states that "the postulated therapeutic range - extrapolated from a previously published pharmacodynamic study - may not be accurate particularly if applied to repeated administration for chronic disease states." The study says that "A placebocontrolled clinical trial will be necessary to confirm which dose would be clinically effective for palliation of chronic nausea and vomiting in cats."
Obviously there are quite sizable differences between these doses. The above study found"Poor bioavailability should be taken into account when determining a route of administration for a patient as individual oral bioavailability ranged from 11 to 50% in the cats used in this study." For acute vomiting, such as in a cat with pancreatitis, higher and/or more frequent dosing may indeed be necessary. For chronic nausea in CKD cats, however, many people find the lower dose is fine, though they may need to give ondansetron twice or even three times daily. I would start with the lower dose of 1 mg each day, and if you find this is not enough, speak to your vet about increasing the dose or frequency.
Chris proved himself the king of not taking pills. I gave him the Cerenia last night around 9. After his SubQ fluids I was setting him in the bed and he calmly spit his Cerenia pill out - an hour and a half after I gave it to him. Goofball.
Hi--I am sending prayers as well… I have a 16 year old with nausea (CRF) been on SQ 5 years etc… I do give him a injection of cerenia now and then but my holistic vet sends me doses (as needed-1 dose lasts almost a month) of Nux Vomica prescription strength…might help? I crush it in the little tiny envelope and dump it in his mouth (surprise attackThanks Ruth. Glad someone brings it up. The vet just put a damn pot-it on the script for the meds to call before giving it with the tramadol the e-vet put him on. Tramadol was on the insert listing for not contra-indicated drugs. When I called the vets office and said I was calling to find out about giving the Mirtz with the Tram, after being on hold for a while the receptionist came back and said the vet needed to look it upA tech called back later and just said that I shouldn't give them together (already figured that out!) and I should wait until 24hrs after stopping the Tramadol. Never bothered to mention the complications (life threatening!) or the signs to watch for.
I did ask about the continuous use of the Cerenia too. Just got told they have lots of patients that use it long term and are fine. My normal vet always has us take the break and prescribes it at a lower dose. I am going to skip it tonight and tomorrow if he seems like he is still not vomiting. I will ask about the ondansetron again on Friday. The oncologist may be avoiding it at this point since he is having constipation issues. He is not vomiting now, but I think there is still nausea there and that is why he won't eat sometimes despite wanting to.
Chris is doing really good right now except he is still constipated, wants to eat but doesn't eat or doesn't eat much, and doesn't seem to want to be out in the sunlight long. He used to bask in the sun, now when he gets too much sun on him he goes back to his sleeping place in the closet.
Thanks everyone for their continued prayers, well wishes, and vines. It means the world.