Not sure, the Vet is probably the best person to BUT our vet has given mum the jab to give to one of our bitches before. So I think yes it should but you should only be able to get it from the vet.
Our vet did leave me with an oxytocin jab once, for a bitch who has having a very stop/start labour. However he did say he wanted to check her when she had finished. So think it probably would be ok as long as it was under vet supervision, rather than people just keeping oxytocin in all the time.