DEAR DR. ROACH: My question is about methocarbamol (Robaxin). My relative has been taking this for about two years for back pain. He then developed a sudden severe allergic reaction and went into anaphylactic shock. He fought it all night, not knowing what was happening, and by morning, he had to go to the hospital. Could this be due to methocarbamol? If so, can this happen again? ...read more read less