Klonopin is an anti-convulsant registered only for use in humans.
Its use in veterinary medicine is infrequent. Although it has been prescribed for use in dogs to control seizures or to aid in controlling anxiety..
However, fairly safe for humans, this drug brings with it some serious side affects when used in dogs.
Your dog neds to be examined by your Veterinarian. If your vet chose to prescribe this particular drug, he would likely suggest doing some blood work to ensure your dog has no underlying organ function problems. This particular drug is to be avoided if there is any existing liver disease especially.
There are in most cases some better choices in prescriptipn medicines for use in the treatment of anxiety in dogs. Talk to your veterinarian.
Hope this was helpful. Good luck.