You're speaking with Dr. Michael Salkin. Welcome to JustAnswer. I'm currently typing up my reply.
This hypnotic is well-tolerated by dogs. A one month oral study in dogs involved giving zopiclone six days per week at doses of 0, 6, 24 and 120 mg/kg. Dose-related sedation and hypotonia (loss of muscle tone) of the hind legs were observed. He ingested just 0.23 mg/kg. There's no need to induce emesis or treat in any manner.
Please respond with further questions or concerns if you wish.
No, I know of no indication for it in dogs. You're quite welcome. I can't set a follow-up in this venue so please return to our conversation - even after rating - with an update at your convenience.
Sedation is all I would expect. Studies support that he's not in danger. There's always the possibility of an idiosyncratic (peculiar reaction) and so I'm pleased to hear that you'll keep watch on him.
Thank you for your kind accept. I appreciate it.