The best way to get your vitamins is in your diet. Commercially produced vitamins are not as readily absorbed by the body.
Incidentally, Magnesium acts as a calcium channel blocker. Lack of magnesium can lead to muscle spasms and, as the blood vessels are muscle (smooth) poor circulation to the extremities and increased blood pressure.
So, before taking beta blockers, it may be a good idea to increase your magnesium intake. Good sources include:
Buckwheat flour
Oat Bran
Almonds
Cashews
Pumpkin Seeds
Spinach
Kale
