They are most often used for pain relief from severe pain and under the supervision of a doctor.

Effects of Opioids

Opioids are a widely researched class of drugs whose effects are well understood. In general, these effects include:

  • Pain relief and sedation
  • Constipation and nausea
  • Respiratory depression (shallow breathing, lowered blood pressure, and reduced heart rate)

Opioids produce these effects through acting on the mu-opioid receptor in the brain. 

Prescription Fentanyl

Fentanyl is one of the most potent opioids approved for medical use. It is intended for chronic pain patients who have developed a tolerance to less potent opioids such as oxycodone or morphine and are no longer achieving therapeutic pain relief. Fentanyl is also used for some surgical procedures because it can be used in smaller doses than other opioids, it is faster-acting, and its effects are more short-lived.

Fentanyl on the Illicit Market

Though diversion of prescription fentanyl has occurred since it first became available, this has never been a major contributor of the increasing supply of fentanyl on the illicit market.  

Fentanyl, fentanyl analogues, and other synthetic opioids are increasingly being produced in underground laboratories. These are often referred to as illicitly-manufactured fentanyls (IMFs) and synthetic opioids. They are now commonly-used as cutting agents to street heroin and other drugs.