MegaMag Magnesium Oxide Nifedipine
ModerateThe leaflet text for magnesium oxide doesn't say anything about nifedipine. It lists other medicines to mention to a doctor before taking magnesium oxide, but nifedipine isn't among them, and the passage cuts off before it ends. So there is no stated effect of taking magnesium oxide and nifedipine together. If you take both, tell your doctor or pharmacist so they can check the combination for you.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.