You posted in the "New Member Introductions" forum at first, and then theotherside26 (a moderator) moved your thread into "Basic Drug Discussion", which is a forum better suited for your question. Then, Cane2theLeft, another moderator, moved your thread to "Other Drugs", a place where your question will most likely be answered in quicker. New Member Introduction is a place for introducing yourself and saying hello to people on bluelight, whereas the other forums are more specialized, which allows different groups of people with different expertise/experience can contribute to specific topics and therefore provide better, quicker, and more accurate information.
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In regards to your question, the Vivitrol shot is a shot of
naltrexone, which is an opioid receptor antagonist much like
naloxone (Narcan, the drug used to counter-act opioid overdoses in emergency situations).
Going from this information, I would say that you will have unpleasant withdrawal reactions if you are on opiates when the Vivitrol/naltrexone is administered.
However, because you were talking about Suboxone, which contains buprenorphine, I'm not entirely sure, because buprenorphine, unlike other opiates such as heroin, morphine, oxycodone, etc, is a competitive agonist, meaning it pushes other drugs out of the receptors and takes their place. I know that buprenorphine is powerful enough to even prevent Narcan/naloxone from entering the receptors.
I am not 100% sure if the same situation exists with Suboxone/buprenorphine and Vivitrol/naltrexone, as Vivitrol and Narcan are indeed different drugs with similar effects, those effects being blocking other opiates from reaching the opiate receptor.
I know this is a big long-winded post and everything, and probably doesn't cover everything, there are other people on this board who are more well-read (and well-experienced) with Suboxone and its interactions with other drugs, but I hope it gets you started in the right direction.
Edit: looks like Cane2theLeft beat me too it, you will probably find even better answers in Other Drugs.