What is the Difference between Nexxium and Priolsec?

I'm under the impression that Nexium is basically Pril0lsec just compounded differently or with something added to it.  I'm asking, because I couldn't tolerate Nexium but can tolerate Priolsec.  I know Nexium is esomeprazole magnesium while Prilosec is Omeprazole.  The doctor doesn't understand why I react with intense itching with Nexium and not Prilosec.
 
Marburg