Oxycodegol
Oxycodegol (also known as loxicodegol and NKTR-181) is an experimental μ-opioid receptor agonist for the treatment of pain. It has had success for back pain as an alternative to traditional opioids, which have potential for abuse. It acts more slowly on the central nervous system, reducing risk for abuse and respiratory depression. References

Mu-opioid receptor agonists
Heterocyclic compounds with 5 rings
Nitrogen heterocycles
Oxygen heterocycles
Methoxy compounds
Experimental drugs