Oh no, what a scare for you. Sounds like something he ate disagreed; you were right to be on the safe side (I think anyone who has been through a fast decline with bleeding gastro or a poisoning never takes something like this casually ). Glad he is seeming a lot better today. It is normal for them to not have to have a bowel movement for a while after they get those injections; they really dry them up and calm the bowel.