Opioid antagonists block the binding of opioids to their target opioid receptors. When opioids or endorphins bind to these opioid receptors, they stimulate the activation of the brain’s reward circuitry. As opioid and endorphin receptors are modulators of dopamine levels, opioid antagonists can help to manage the activation of the reward circuitry.
There are 3 opioid antagonists approved by the U.S. Food and Drug Administration (FDA): nalmefene, naltrexone, and naloxone. Development of nalmefene as a treatment for alcohol dependency was pioneered by Dr. David Sinclair using the principles of harm reduction and symptom-driven treatment. Currently, nalmefene is formulated as an oral tablet for alcohol dependency in Europe. Naltrexone is administered as an oral tablet or by depot injection to treat alcohol and substance use dependency.
Today, naloxone is used by paramedics and physicians to reverse the respiratory depression that is caused by opioid overdose. It is currently approved only as an injectable drug, which limits its availability of use. Opiant’s naloxone nasal spray allows a much larger population to administer treatment quickly and safely.