Robaxin medication side effects may include anaphylaxis, swelling, fever, headache, slow heart rate, flushing, low blood pressure, fainting, thrombophlebitis, indigestion, yellowing of the skin or whites of the eyes, nausea, vomiting, memory problems, confusion, vision problems, dizziness, drowsiness, sleep problems, muscle incoordination, sedation, seizures, nasal congestion, metallic taste, itching, rash, and hives. If you have any side effects that bother you or won't go away, call your doctor right away.