I've never taken Xanax, though I haven't encountered any conflicts with Miracle-Mineral-Supplement and prescriptions beyond Benadryl and IV antihistamine. Which was interesting as both seemed to interfere with the effectiveness of Miracle-Mineral-Supplement rather than the other way around.
That being said, you should really seek natural alternatives to Xanax as I've heard some pretty nasty things associated with this particular drug. Especially if consider that most anxiety problems are linked to mineral and/or vitamin deficiencies. ie, magnesium(epsom salt) baths and supplements(oil) often help people with anxiety. Likewise, electrolyte drinks such as Gastrolyte have been known to induce significant calmn in many chronic anxiety sufferers. And least but not last, prayer and meditation can often help a great deal.
Hope this helps.
PS. When I first started drinking wheat grass, I felt so relaxed afterward that I felt like I was floating on air. This lasted several days until I got used to it. My doctor told me it was likely due to a severe lack of a mineral that body was finally getting replenished. I suspect Iron though that's just a guess.