Arthrotec is just Voltaren (an RX NSAID like ibuprofen) mixed with a PGE1 drug that help prevent stomach erosions.

Amrix is long acting Flexeril, and that is a good muscle relaxant.
I use Flexeril myself occasionally. It find it quite sedating, but others deal with it well. You may find additive sedation with Xanax, and may not even need the Xanax while on Amrix. But if you take Xanax every single day, you cannot stop it suddenly.
Flexeril comes in an immediate release form, which you can split in half to reduce side effects. You can request this type so you can take it more safely with your Xanax.

Nothing spooky in either. Long term use of Arthrotec may affect the liver, but short term use is not a big deal.