I could take neither of these drugs, and my very smart neurologist put me on Magnesium to control night time spasm and jerking of lower back and legs. That was decades ago, and I still must take Magnesium. 800 mg a day is the lowest, sometimes need 900. I believe calcium and Vitamin D are natural things to go with this. But I take the calcium between meals and not at the same time as the magnesium.