One, Oxytocin, is a hormone; Oxycontin is a frequently prescribed narcotic painkiller.

The effects of oxycodone include pain relief, euphoria, anxiolysis, feelings of relaxation, and respiratory depression plus numerous side-effects.

Oxytocin (Oxt) is a human peptide hormone plays a role in social bonding, sexual reproduction in both sexes, and during and after childbirth.

I had the same confusion when I watched this video:

https://www.ted.com/talks/paul_zak_trust_morality_and_oxytoc...

They are completely different substances.