how does Suboxone work?

Suboxone is a combination medication containing 2 active ingredients: buprenorphine and naloxone.

1) Buprenorphine, the major ingredient of Suboxone, is a partial opioid agonist. As an agonist, it binds to the receptors in the brain that are responsible for opioid actions, such as pain relief and euphoria. Buprenorphine has high affinity for these receptors and therefore is not displaced by other agonists such as oxycodone or morphine if taken later. On the other hand, as a partial agonist, it does not produce as much euphoria but it does suppress withdrawal and cravings. In other words, although buprenorphine is still an opioid with effects such as pain relief and euphoria, its maximal effects are less than those of full agonists like heroin and methadone.  
At low doses, buprenorphine produces sufficient agonist effects to enable opioid-addicted individuals to discontinue the misuse of opioids without experiencing withdrawal symptoms. The agonist effects of buprenorphine increase linearly with increasing doses of the drug until at moderate doses (8-16 mg per day) they reach a plateau and no longer continue to increase with further increases in dose—the “ceiling effect”. Therefore, no more noticeable effects are seen for doses above 24-32 mg per day. This ceiling effect is seen only in partial agonist. Full agonists such as oxycodone, morphine and methadone have no celing effect, thus exerting stronger effects and side effect with increasing dosage. It is for these reasons that buprenorphine carries a lower risk of abuse, addiction, overdose and side effects compared to full opioid agonists. 

In high doses and under certain circumstances, buprenorphine can actually block the effects of full opioid agonists and can precipitate withdrawal symptoms if administered to an opioid-addicted individual while a full agonist like morphine or oxycodone is in the bloodstream.

Like methadone, buprenorphine has a slow and long metabolism, unlike commonly known opioids such as oxycodone (OxyContin® or Percocet®), fentanyl, hydromorphone (Dilaudid®), heroin, morphine, codeine, etc.  While such other opioids reach peak action within minutes or seconds (if injected or inhaled), suboxone can take some hours to reach its peak action. Due this slower metabolism, suboxone stays in the body much longer too -often days as opposed to hours. This allows a more even and stable action of the medication as opposed to the rapid onset and offset of a short acting opioid such as morphine or oxycodone. So while buprenorphine exerts its opiate-like effect, it does it in a slower and more controlled way. This effect is one that is desired for an individual addicted to the euphoria or "high" achieved from the rapid-acting opioids. While buprenorphine provides relief from the symptoms of withdrawal such as aches, chills, and cramps and the mental effects of craving for the high, it does not produce a high itself.

Buprenorphine has poor oral absorption and therefore, the medication is not available in an oral form.  The tablets must be dissolved and absorbed from the mouth under the tongue. 

2) Naloxone is the other active ingredient of Soboxone.  It is a full opioid antagonist that can only be absorbed via injection.  An antagonist is a medication that reverses the actions of an agonist.  Naloxone is not orally or sublingually absorbed. Naloxone will be active only when injected. Due to its antagonist properties, if injected, it will cause immediate and full precipitation of withdrawal from any opioids present in the body.  The naloxone is added to Suboxone to decrease its abuse potential and discourage the injection use of Suboxone for purposes of achieving euphoria.