I used to take Nexium. But I can't address magnesium since I don't take it other than what is in the Citracal. But I was checked recently for any malabsorption issues and I don't have any deficiencies. But, the problem with me is...Nexium didn't or doesn't last through the night. So, I was switched to Zegerid which I LOVE! And I know someone will come along and say it is just Prilosec or Nexium with sodium bicarbonate added. But I don't care...it works wonderfully! The only thing I have read is that if you are on a low salt diet you have to be careful. But so far so good! I now wake up WITHOUT nausea or any heartburn even after taking my meds of an evening. You might consider asking your Gastro doc about it since you have ongoing hearburn. I had the same thing happening basically and I can't sleep with my head elevated due to my spinal fusions. It is expensive. I picked up my first script yesterday but since my insurance is good it was only $28.00.