Commonly Used Terms

Key points

Below is a list of commonly used terms in reference to opioids and drug overdose.

Commonly used terms

  • Analog – Drugs that are similar in chemical structure or pharmacologic effect to another drug but are not identical.
  • Benzodiazepines – Sometimes called "benzos," these are sedatives often used to prevent seizures and treat anxiety disorders, insomnia, and other conditions. Examples include alprazolam (Xanax®), diazepam (Valium®), and lorazepam (Ativan®). They can be misused and have addiction potential. Combining benzodiazepines with opioids increases a person's risk of overdose and death.123
  • Fentanyl – A synthetic opioid that is up to 50 times stronger than heroin and 100 times stronger than morphine.45 There are two types of fentanyl: pharmaceutical fentanyl and illegally made fentanyl. Pharmaceutical fentanyl is approved for treating severe pain, typically advanced cancer pain. It is prescribed in the form of transdermal patches or lozenges. Illegally made fentanyl is sold through illicit drug markets for its heroin-like effect.
  • Heroin – An illegal opioid drug processed from morphine and extracted from certain poppy plants.
  • Illegal drugs – A variety of drugs that are prohibited by law. These drugs can include: amphetamine-type stimulants, marijuana/cannabis, cocaine, heroin, other opioids, and synthetic drugs, such as illicitly manufactured fentanyl (IMF) and ecstasy (MDMA).
  • Medications for opioid use disorder (MOUD) – Treatment option for opioid use disorder using medications such as methadone, buprenorphine, or naltrexone.
  • Methamphetamine – A highly addictive central nervous system stimulant also categorized as a psychostimulant. Methamphetamine use is linked to mental disorders, problems with physical health, violent behavior, and overdose deaths.67 Methamphetamine is commonly referred to as meth, ice, speed, and crystal, among many other terms.
  • Naloxone – A life-saving medication that can reverse an overdose from opioids – including heroin, fentanyl, and prescription opioid medications – when given in time.
  • Nonopioid therapy – Methods of managing pain that do not involve prescription opioids. These methods can include, but are not limited to, acetaminophen (Tylenol®) or ibuprofen (Advil®), naproxen (Aleve®), cognitive behavioral therapy, physical therapy, acupuncture, meditation, exercise, some medications for depression or for seizures, or interventional therapies (injections).
  • Non-pharmacologic therapy – Treatments for pain that do not involve medications, including physical treatments (e.g., exercise therapy, weight loss, mind-body practices, acupuncture) and behavioral treatments (e.g., cognitive behavioral therapy).
  • Opioid – Chemicals that interact with opioid receptors on nerve cells in the body and brain, and reduce the intensity of pain signals and feelings of pain. This class of drugs includes the illegal drug heroin, illegally made fentanyl, and pain medications available legally by prescription, such as oxycodone, hydrocodone, codeine, morphine, prescribed fentanyl, and many others. Prescription opioids can be safe when taken for a short time and as directed by a doctor, but because they produce euphoria in addition to pain relief, they can be misused and have addiction potential.
  • Overdose – Injury to the body (poisoning) that happens when a drug is taken in excessive amounts.
  • Overamping – An overdose of stimulants such as methamphetamine or cocaine. Symptoms can include cardiac symptoms, such as chest pains or heart palpitations, or individuals may appear to be experiencing a stroke. Some people experience psychiatric symptoms, such as agitation, delirium, or trauma.
  • Pain
    • Acute pain: Pain that has lasted for less than a month. It usually starts suddenly and has a known cause, like an injury, trauma, surgery, or infection. It normally gets better as your body heals.
    • Subacute pain: Pain that lasts at least 1 month but not more than 3 months. Painful acute conditions include: low back pain, neck pain, broken bones, muscle sprains or strains, dental pain from infection or tooth extraction, pain due to kidney stones, acute episodic migraines, and pain after surgery.
    • Chronic pain: Pain that lasts more than 3 months. It can be caused by a disease or condition, injury, medical treatment, inflammation, or even an unknown reason. Sometimes acute or subacute pain that is not effectively managed becomes chronic pain.
  • Prescription drug misuse – The use of prescribed medications in any way not directed by a doctor, including use without a prescription of one's own; use in greater amounts, more often, or longer than instructed; or use in any other way not directed by a doctor.
  • Prescription drug monitoring programs (PDMPs) – State or territorial-run electronic databases that track controlled substance prescriptions. PDMPs help clinicians identify patients at risk of opioid misuse, opioid use disorder, and/or overdose due to overlapping prescriptions, high dosages, or co-prescribing of opioids with benzodiazepines.
  • Prescription opioids – Medications used to treat moderate to severe pain in some patients. Categories of prescription opioids:
    • Natural opioids, these come from the poppy plant and include morphine and codeine;
    • Synthetic opioids (other than methadone) are made in a laboratory, and include drugs such as tramadol and fentanyl;
    • Semi-synthetic opioids, including drugs such as oxycodone, hydrocodone, hydromorphone, and oxymorphone; and
    • Methadone, a synthetic opioid that can be prescribed for pain reduction or for use as a medication for opioid use disorder (MOUD). For MOUD, methadone is used under direct supervision of a healthcare professional.
  • Substance Use Disorder(s) (SUD) – A substance use disorder is a cluster of cognitive, behavioral, and physiological symptoms indicating that the individual continues using the substance despite significant substance-related problems. "Substance use disorders" is preferred over the term "addiction."

What is the difference between “tolerance,” “dependence,” and “opioid use disorder”?

Opioid tolerance occurs when a person using opioids begins to experience a reduced response to medication, requiring more opioids to experience the same effect.

Opioid dependence occurs when the body adjusts its normal functioning around regular opioid use. Unpleasant physical symptoms occur when opioids are stopped.

Opioid use disorder (OUD) - A problematic pattern of opioid use that causes significant impairment or distress. A diagnosis is based on specific criteria such as unsuccessful efforts to cut down or control use, or use resulting in social problems and a failure to fulfill obligations at work, school, or home, among other criteria. Opioid use disorder is preferred over other terms with similar definitions, "opioid abuse or dependence" or "opioid addiction."

  1. Liu S, O’Donnell J, Gladden RM, McGlone L, Chowdhury F. Trends in Nonfatal and Fatal Overdoses Involving Benzodiazepines — 38 States and the District of Columbia, 2019–2020. MMWR Morb Mortal Wkly Rep 2021;70:1136–1141. DOI:
  2. Sun EC, Dixit A, Humphreys K, Darnall BD, Baker LC, Mackey S. Association between concurrent use of prescription opioids and benzodiazepines and overdose: retrospective analysis. BMJ. 2017;356:j760. Published 2017 Mar 14. doi:10.1136/bmj.j760
  3. Dasgupta N, Funk MJ, Proescholdbell S, Hirsch A, Ribisl KM, Marshall S. Cohort study of the impact of high-dose opioid analgesics on overdose mortality. Pain Med. 2016;17(1):85-98. doi:10.1111/pme.12907
  4. Suzuki J, El-Haddad S. A review: Fentanyl and non-pharmaceutical fentanyls. Drug and Alcohol Dependence. 2017; 171:107–116.
  5. Ciccaron, D. Editorial for "US Heroin in Transition: supply changes, fentanyl adulteration and consequences." International Journal of Drug Policy. 2017;46:107-111.
  6. Barr AM, Panenka WJ, MacEwan GW, et al. The need for speed: an update on methamphetamine addiction. J Psychiatry Neurosci 2006;31:301–13.
  7. Degenhardt L, Sara G, McKetin R, et al. Crystalline methamphetamine use and methamphetamine-related harms in Australia. Drug Alcohol Rev 2017;36:160–70.