You're speaking with Dr. Michael Salkin. Welcome to JustAnswer. I'm currently typing up my reply.
20 mL would be an egregious overdose. Dosing of this drug is 1 mg/kg. The injectable solution contains 10 mg/mL of maropitant (Cerenia). A 12 kg dog, then, should receive 12 mg or 1.2 mL of the solution. Please respond with further questions or concerns if you wish.
Perhaps the Cerenia was placed in saline which would dilute it and then take the sting away when injected? I can't imagine any (sane) vet injecting such a volume of that drug. There are no toxicity studies involving such an egregious overdose in dogs but in rats given 100 mg/kg orally no adverse events were reported. At 2.5 mg/kg IV rats had decreased activity, irregular or labored respiration, ataxia ("drunken sailor") and tremors.
Please continue our conversation if you wish.
Ah! "Cerenia solution 20ml inj." identifies the product used...not the dose given. Cerenia comes in 20 mL vials of 10 mg/mL maropitant. Please continue our conversation if you wish.
Practices post the exact doses in the medical record. For billing purposes only the product used is posted (privacy concerns). A 20 mL injection wasn't given now that I can see what you saw in that image. A pathologist will look at the entire body or only areas of import predicated upon the cause of death. A vet can request a "full" necropsy or a look at just one organ.
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