In 2022, nearly 110,000 Americans died from drug overdoses. More than 81,000 of these deaths involved either prescription or illicit opioids and increase of approximately 400 percent over a decade. The vast majority, nearly 74,000, of these deaths involved the synthetic opioid fentanyl.

Opioids are natural, semi-synthetic, or synthetic molecules that interact with opioid receptors. Opioid receptors are expressed in different organs throughout the brain and body and control many aspects of body function, including pain, breathing, intestinal function, and even the size of the pupil. Opioid receptors cannot tell the difference between opioids that are made naturally by the body, such as endorphins, opioids that are produced by plants, such as heroin from the opium poppy or mitragynine from kratom (‘opiates’), or opioids that are created in a laboratory, such as fentanyl and loperamide (‘synthetic opioids’). While the terms ‘opioids’ and ‘opiates’ are sometimes used interchangeably, ‘opiate’ refers specifically to natural compounds, such as heroin or morphine, while opioids includes both naturally-occurring opiates and those created in a lab.

There are many different naturally occurring and synthetic opioids. The main differences between these are 1) how strongly they activate opioid receptors and 2) the length of time that they are active in the body. For example, heroin is two times stronger than morphine, while fentanyl is 50 times stronger than heroin. Fentanyl lasts for hours, while the effect of methadone can last much longer.(1,2,3)

Prescription opioids are mainly used to treat acute pain (in the emergency department or after a surgical procedure), chronic pain, cancer-related pain, palliative care, and end-of-life care. They are also sometimes used for sedation during a procedure. Less potent opioids are also used as cough suppressants and to treat diarrhea. Opioids are very effective for relieving pain. Examples of prescription opioids include oxycodone (OxyContin®) hydrocodone (Vicodin®), codeine, morphine, and others. Synthetic opioids include fentanyl, methadone, and tramadol.

Because opioids work on all of the opioid receptors in the body, when they are used to reduce pain, they also commonly cause side effects, including drowsiness, confusion, euphoria (the experience of being “high”), nausea, and constipation. Opioids may be used recreationally to purposefully cause these side effects and “get high”. At doses that are above the safe maximum level (“overdose”), opioids can cause extremely slow breathing, reducing the amount of oxygen getting to the brain below the amount needed to stay alive and causing death.

According to provisional data, the Centers for Disease Control and Prevention (CDC) estimates nearly 87,000 drug overdose deaths occurred in the 12-month period ending September 2024.(4) The opioid crisis was declared a nationwide Public Health Emergency on Oct. 27, 2017. By June 2021, synthetic opioids were involved in an estimated 87% of opioid deaths and 65% of all drug overdose deaths.(5) This has made opioid overdose a leading cause of death in the United States.(6)

Figures 1 and 2: NIDA, Drug Overdose Deaths: Facts and Figures, https://nida.nih.gov/research-topics/trends-statistics/overdose-death-rates

Opioids produce feelings of euphoria that make it more likely that people will continue to use opioids, despite any negative consequences that may go along with opioid use. Opioid use disorder (‘OUD’ – opioid addiction) is a chronic, medical disease, with serious potential consequences including disability, relapse, and death. The Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, Text Revision (DSM 5-TR) describes OUD as a pattern of opioid use leading to problems or distress, where at least two of the following occurring within a 12-month period:

1. Taking larger amounts or taking drugs over a longer period than intended.
2. Persistent desire or unsuccessful efforts to cut down or control opioid use.
3. Spending a great deal of time obtaining or using the opioid or recovering from its effects. 
4. Craving, or a strong desire or urge to use opioids
5. Problems fulfilling obligations at work, school or home. 
6. Continued opioid use despite having recurring social or interpersonal problems. 
7. Giving up or reducing activities because of opioid use. 
8. Using opioids in physically hazardous situations such as driving while under the influence of opiates.
9. Continued opioid use despite ongoing physical or psychological problem likely to have been caused or worsened by opioids. 
10. Tolerance (i.e., need for increased amounts or diminished effect with continued use of the same amount)* 
11. Experiencing withdrawal (opioid withdrawal syndrome) or taking opioids (or a closely related substance) to relieve or avoid withdrawal symptoms.*