Are Demerol and morphine the same?

Mepergan Forte contains the opioid pain reliever Meperidine, also known as Demerol and the antinausea medication Promethazine also known as Phenergan. Promethazine is from the phenothiazine class of medications. It is often administered in combination with an opioid, like Meperidine, to minimize the nausea that is caused by pain medication. The product Mepergan Forte is taken in oral form and contains both Meperidine for pain, and Promethazine for nausea.