I am currently on Protonix (although I believe my body is trying to defeat it...), but I am not quite sure on how long it takes Nexium to work. With my guess, it will take a little longer than two weeks, due to the damage that the acid has done to your esophagus. However, I do not know your exact case, so my best bet would be to consult your doctor and let him know what's going on before increasing the amount of medicine that you are taking. AS well, possibly try messing around with when you take your Nexium. Possibly take your first pill, and then wait 30 minutes or so before eating. Hope I could help, and GOOD LUCK