The active ingredient in AMRIX is cyclobenzaprine hydrochloride, (three rings) while ibuprofen is p - isobutylphenyl (one ring) and aspirin is acetysalicylic acid (one ring).
So I dont see any cross alergencity because of this.
So you can take it; if you are not alergic to AMRIX by itself.
Moreover you cannot take amrix for longtime.
and you can test by taking a very low dose or drug to check for any problems first. and later increasing to recomended levels.
and Dont mix side effects with allergy , thse two are totally diffent entities.
Hope this answers ur question / concern to some extent.