You can read about Nexium here in the drugs database. In the instructions it doesn't say that you can not or should not take Nexium prior to going to bed, only that you should take it at the same time each day.
Are you having nighttime symptoms and that is why you want to take the medicine at night? You can read how to relieve some of the night time symptoms here in this article by Tracy Davenport. While the article is written with children in mind, it still applies to adults too. There is also a good overview that has some advice for adults with acid reflux, lifestyle and dietary changes to be aware of to prevent acid reflux. You can read about that here.
I hope this helps. Let us know how you are doing! If you find taking the Nexium at night improves your condition, please let us know!Vicki M
I have been taking Nexium at night and it worked extremely well. Recently, a doctor told me that I should take it in the mornings half hour to an hour before breakfast. It does not work as well as at night for me. When I take it in the morning it seems to trigger a desire to have a bowel movement. Also when I take it at night it seems to be more effective preventing burping at night. I am looking for answers regarding the best time to take it myself.
I have been taking Somac which is like Nexium for four years. I found that if I take it a half an hour before breakfast in the morning each day it works much better than when I take it at night or any other time. Might be as my stomach is empty in the morning, not sure, but it works well for me : -)