My boyfriend does meth AND sub strips together 2 or 3 times a month. When he does he gets so high for 2 or 3 days and will not shut up talking! You can't get a word in, it drives me crazy!! Then he starts nodding off on the 2nd or 3rd day which is even worse! He finally crashes and sleeps for as many days as he was up. So no....it does not block meth. His DOC is opiates and was on methadone for 30 yrs give or take. He kicked it after going to jail for a short stint. He now only does sub strips 2 or 3 times a month and he gets his fix when he mixes it with meth. I am only a meth user and have never done heroine or opiates except when in the hospital having a baby. I do not like it that he does opiates. I have never been with anyone who uses opiates. So I have a lot of questions about opiates and people who use them. I do not always think he is being honest with me about what he is doing.....like is he doing H and not telling me, or is he only doing sub strips like he says. I wouldnt know the difference.