Gabapentin after neutering

My boy cat (10 months) just got neutered today and he is running around the house, jumping on everything, and super aggressive. I know this is technically normal after the surgery, however he can’t seem to calm down or get comfortable. He was prescribed gabapentin for his aggressiveness by his vet for when he came in to get neutered but I ended up going to a different place to get it done. Would it be bad if i gave him a dose now to calm him down for the night and sleep?