Similar uses

• Nexium and Prilosec are both also used to treat GERD (gastroesophageal reflux disease), healing erosion of the esophagus due to stomach acid and also in the treatment of ulcers.
  
  

Different uses

• Nexium is also used specifically to treat Zollinger-Ellison syndrome, which causes gastrin- (stomach acid) secreting tumors.
  
  

Similar side effects

• Nexium and Prilosec have the same reported common side effects of headache, nausea, diarrhea, gas, stomach pain and constipation.
  
  

Different side effects

• Nexium has an additional common side effect of dry mouth that Prilosec does not.
  
  

Dosing

• Nexium is taken once daily in either 20 milligram or 40 milligram capsules for a period of four to eight weeks. It may be taken longer, but generally treatment falls within these parameters. Prilosec is taken once daily in either 10 milligram, 20 milligram or 40 milligram capsules and can be used for long-term management of acid prevention.
  
  

Availability

• Perhaps the biggest difference between these two medications is their availability. Nexium is available by prescription only, and Prilosec is available over the counter.