Oxycodone
Since 2014, a new mixture has been created.  It is a mixture of oxycodone and naloxone.  Its goal is to stop people from abusing long-acting oxycodone.  (See the "Addiction" section lower on this page).  People sometimes abuse long-acting oxycodone (OxyContin) by chewing, crushing, snorting, or injecting the pills.  When oxycodone is mixed with naloxone, if the medicine is swallowed by mouth, like it is supposed to be, the oxycodone works like normal.  But if the medicine is chewed, crushed, or dissolved, the naloxone inside is released.  The naloxone keeps the oxycodone from working in the brain.  This makes it impossible for the person to get the good feelings they wanted to get from abusing the oxycodone.