My dentist once gave me some Methocarbamol?? For muscle spasms I was having in my jaw that was giving me headaches. I took them twice and both times ended up with an episode of Scintillating Scotomas. You know the eye thing with the electric arc. Never took them again after the second incident. I couldn't GET a doctor to give me Flexeril again so I have had to resort to a less physically demanding lifestyle and OTC back pain med MOMENTUM which I take with 2 Tylenol then lay down for an hour and it really helps. Plus I take extra Potassium a few times a week, That helps too.