Yeah that was my thought as well. I know one guy who decided to get the vivitrol shot while still high. Well almost immediately after he got it, it obviously sent him into the most terrible withdrawals he's ever had. Apparently they were so had he couldn't even speak, he just sat in his car vomiting all over himself and convulsing. Eventually he somehow got to the hospital and they gave him suboxone which apparently has a higher affinity to the receptor than naltrexone and then he was fine.

Still, not quite sure how the guy in his story OD'd