Hello and Thank You for contacting JustAnswer,
Can you tell me how long ago this happened?
Since it has been longer the 2 hours inducing vomiting will not likely have and effect.
Cyclobenzaprine is a muscle relaxant as you know.At this dose it is possible to see the following side effects tachycardia (rapid heart rate), constipation, dilated pupils, vomiting, drowsiness, ataxia, seizures, and respiratory depression.
This is not a medication that is used in dogs and because of the high dose I would suggest having her seen by a vet right away. They will be able to administer activated charcoal to prevent further absorption monitor the heart rate and breathing and provide IV fluids to help flush this from the system.
I hope he does ok,please reply back if you have additional questions or concerns.