Is it safe to mix Subutex with Skelaxin?

A friend of mine has taken Suboxone every day for over two years. When I mentioned Subutex, I meant pure Buprenorphine without Naloxone. That needs to be clear, because sometimes people get Suboxone and Subutex mixed up..He takes around 24-32mg every day....8-16mg sublingually and/or 8-16mg nasally. Would it be safe for him to take Skelaxin with Subutex? I know that Skelaxin is a muscle relaxant, but it also contains pain relieving qualities. He's been wanting to mix the two. But I want to make sure it's safe for him to mix the two. I've become very-well educated about prescription meds because of him. But I have found very little information about mixing these two medications online. I'd appreciate any anyone who has knowledge about or experience with mixing these two.drugs to please share your experience so I can relate it to him.