An extremely powerful, fictional drug used by people throughout Kim Stanley Robinson's Mars Trilogy.
First mentioned usage is by John Boone on page 239 in Red Mars:
"In fact he took a break
and went back to the bathroom in his room to swallowed
a capsule manufactured by Vlad's medical group on Acheron.
It was a drug they had named omegendorph, a synthetic
mix of endorphins and opiates they had found in
the brain's natural chemistry, and a better feel-good drug
than Boone would have imagined possible."

See Also:
John Boone
Red Mars
Green Mars
Blue Mars
The Martians
Mars Trilogy