I felt so bad for my Chihuahua the other night. She was doing fine while laying down with me watching tv. A couple minutes later I put her in the kennel, she was fine but then she started making noise. So I walked over and opened the door from the kennel, thinking she probably had to go to the restroom. But instead she couldn't walk, her eyes were rolled back,and she was shaking all over. I felt so bad and scared beacuse it lasted for a long time. Finally when it was over you could she didn't know what had happened, and it seemed she forgot how to walk for a couple seconds. It has not been the first time she has had one, but it has been awhile.
My dog has seizures. They are really scary the first time it happened I thought he was choking and was going to die. I completely flipped out. It is common that dogs have a couple seziures in their lifetime. For the first two years my dog only had one once every few months and the vet did not put him on medication because it causes liver damage. Once the seizures become more frequent (once a month) we put him on medication because seizures cause brain damage. The vet was great and worked with us to put him on the lowest dose possible so he wouldn't be dopey and he is fine. I would recommend you tell your vet about it because sometimes there can be another cause, i.e. something he ate, medicines, etc.
Seizures can be so scary I am sorry your dog had one. I find that eventhough he is completely out of it I pick up my dog and pet him and talk to him while he is having one, so maybe he knows someone is there.
I used to have a dog and she had a one seizure in her fifteen years of life. It was really scary b/c I couldn't do anything to stop it or to help her. But we took her to the vet and everything checked out okay and she never had one again.