My dog accidentally swallowed a pill that isn't for dogs, should I take him to the vet?

I am in the process of cleaning my room and a bottle of pills fell off my desk and popped open. I cleaned them all up, except for one which my dog ate before I could grab it. It was only half a pill that he ate. It was Prozac, I can’t remember the dosage because it wasn’t in the original pill bottle. Should I be concerned over this or will my dog be fine?