Vitamins, herbs and supplements can affect the absorption of medications. Find out from your neurologist which ones to avoid. (Magnesium is a concern for many MGers).
Also, vitamins herbs and supplements are manufactured by companies that have no regulation and monitoring. There is no way to know what their true ingredients and dosages are. I would steer far away from them.
Our organs are not designed to process and filter high concentrations of minerals and vitamins. Finding what you are deficient in and adding that vitamin or mineral to your diet, naturally, is much safer.