Buprenex after a premolars extraction

My 10 year old cat just had a routine cleaning and a lower premolar extraction. He was given an injection of Buprenex at the veterinarian's office and follow up oral Buprenex for 5 days with the first dose the same evening. The Rx was 0.7 ml by mouth twice daily. He weighs about 15.8 lbs. (Norwegian Forest cat). I called the veterinarian the next morning and explained his symptoms he was experiencing from the time I picked him up (extremely hyperactive, running in circles, could not walk without his legs slipping out from under him, and then did not sleep for two days).
I was told to reduce the dosage, that each cat is different. In the end I reduced the dosage to 0.3 ml which keeps him happy, but still allows him to get the sleep he needs to heal. Any thoughts on this?

My experience with buprenorphine ( I think is the same as buprenex) comes from cat sitting my friend's elderly cat. She's on it all the time now, twice a day. She just gets a tiny amount - around .5ml squirted on her gums. It still makes a difference to manage her pain, but doesn't affect her behaviour. The medication that does effect her is Tramadol, and she behaves similarly to what you described your cat doing.
Anyway, the vets told my friend she could reduce the dose of her "squirties" as Hobbes is such a tiny, elderly cat. Initially she was at a higher dose. They said it was very individual and cats react differently to it so it doesn't surprise me what your vet has told you.
I hope your cat heals up quickly. Is that him in your avatar? He's gorgeous!

Thank you for your reply. It is the same drug and he is doing much better after being on a reduced dosage. He (Pepe) is the one in the picture. As a kitten he was living in a hollowed out log with his mother and a sibling near a resort where they would come to beg for food. A friend brought him to me and he has been a joy to have for the last 9 yrs. All of my cats have been rescued in some way, but I only have 2 at any given time. My last cat passed away at age 19 after 15 yrs. with us. Pepe has a new friend from a shelter from the day after Christmas. I hope Hobbes continues to do well on the pain med also.