What Are Opiates?

Poppy pods and poppy flower

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Opiates, sometimes known as narcotics, are a type of drug that act as depressants on the central nervous system (CNS). Opiates come from opium, which can be produced naturally from poppy plants; opioids are chemically synthesized opiate-like drugs.

Some of the most common opiates and opioids include:

  • Morphine (Kadian, Avinza)
  • Codeine
  • Hydrocodone (Vicodin)
  • Fentanyl
  • Oxycodone (OxyContin, Percocet)
  • Heroin

Opiates Definition

Opiates can be defined as any drug that comes from the opium alkaloid compounds that naturally occur in the poppy plant. These substances affect the opioid receptors in the brain and body to produce pain relief. 

Opiates vs. Opioids

While an opiate is a naturally occurring compound found in poppy plants, an opioid refers to any substance, whether natural or synthetic, that binds to the opioid receptors in the brain to create opiate-like effects. 

Types of Opiates

There are a few different types of opiates: 

  • Codeine
  • Morphine
  • Opium
  • Thebaine

Morphine and codeine are the two most common opiates. Thebaine is not used on its own as a pain medication, but it is used to produce synthetic opioid pain medications, including hydrocodone and buprenorphine.

There are also a number of different synthetic and semi-synthetic opioids that have effects similar to those of natural opiates. Some of these include heroin, oxycodone, and methadone.

How Opiates Affect the Brain

Both humans and animals have opiate receptors in the brain. These receptors act as action sites for different types of opiates, such as heroin and morphine.

The reason the brain has these receptor sites is because of the existence of endogenous (internal) neurotransmitters that act on these receptor sites and produce responses in the body that are similar to those of opiate drugs.

Opiates and opioids work by binding to specific receptors in the brain, mimicking the effects of pain-relieving chemicals that are produced naturally.

These drugs bind to opiate receptors in the brain, spinal cord, and other locations in the body. This blocks the perception of pain.

Side Effects

While opiates can relieve pain and create feelings of euphoria, they can also produce a number of unwanted side effects.

  • Confusion
  • Constipation
  • Dependence
  • Dizziness
  • Drowsiness
  • Hypoxia
  • Nausea
  • Overdose
  • Slowed breathing
  • Tolerance
  • Vomiting


Opiates can cause feelings of well-being, but they can also cause side effects such as nausea, confusion, and drowsiness.

Tolerance, Dependence, and Withdrawal

In addition to relieving pain, opiates can lead to feelings of euphoria. While these drugs are often very effective in treating pain, people can eventually develop a tolerance, so they require higher doses to achieve the same effects.

As opiate drugs become more tolerated, people may begin taking increasingly higher doses to experience the same pain-relieving effects and reduce symptoms of withdrawal. Symptoms of opiate withdrawal can include:

Abdominal cramping

  • Anxiety
  • Insomnia
  • Irritability
  • Muscle aches
  • Nausea
  • Runny nose
  • Vomiting

What makes prescription opiates so potentially dangerous? They affect powerful reward systems in the brain. Over time, the brain needs these substances to continue experiencing rewards and avoid withdrawal.

Some people can even become addicted when taking them exactly as prescribed, but the dangers can be increased by not taking them as directed or by combining them with other substances, including alcohol and other drugs. Also, there are individual differences in genetic vulnerability to opiate addiction.

The risk of developing an addiction to opiates or opioids increases when taking high doses, when using these medications for prolonged durations, or when using extended-release or long-acting formulations.

Other risk factors include being younger, past substance use, environments that encourage use, and untreated mental health conditions.

Opiate Misuse

Opiate and opioid use are on the rise globally, so it may come as no surprise that abuse and addiction to such substances have also increased in recent years. According to official statistics:

  • Opioid prescriptions peaked in 2012 and have declined since. While overall rates have dropped, the Centers for Disease Control and Prevention notes that it remains high in certain areas of the U.S., with more than 142 million opioid prescriptions in 2020.
  • In 2019, opioids were involves in 49,860 overdose deaths. This accounts for 70.6% of all drug overdose deaths.
  • About 75% of all people with an opioid addiction disorder end up switching to heroin as a cheaper source of opioids. Nearly half a million U.S. adults are addicted to heroin.

The CDC also reports that opioid deaths remained steady between 2010 and 2018 but increased significantly after, with 68,630 deaths in 2020.

A Word From Verywell

An estimated 50 million adults in the U.S. experience some type of chronic pain. Opioid pain relievers are often prescribed to treat injury-related pain, dental pain, and back pain.

When taken as directed, they are generally not likely to lead to overuse or addiction. People who use opiates to control pain should contact their healthcare provider if they believe they may be developing a tolerance or addiction.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

For more mental health resources, see our National Helpline Database.

13 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute on Drug Abuse. Opioids.

  2. King E. Centers for Disease Control and Prevention. RIDOH State Health Laboratories. The opioid epidemic: What labs have to do with it?

  3. U.S. National Library of Medicine. Thebaine.

  4. Benyamin R, Trescot AM, Datta S, Buenaventura R, Adlaka R, Sehgal N, Glaser SE, Vallejo R. Opioid complications and side effects. Pain Physician. 2008;11(2 Suppl):S105-20. PMID: 18443635.

  5. Shah M, Huecker MR. Opioid withdrawal. In: StatPearls [Internet]. StatPearls Publishing.

  6. National Institute on Drug Abuse. Introducing the human brain. Drugs, Brain, and Behavior: The Science of Addiction.

  7. U.S. Department of Labor. Risk factors for opioid misuse, addiction, and overdose.

  8. Webster LR. Risk factors for opioid-use disorder and overdose. Anesth Analg. 2017;125(5):1741-1748. doi:10.1213/ANE.0000000000002496

  9. Centers for Disease Control and Prevention. U.S. opioid prescribing rate maps.

  10. Centers for Disease Control and Prevention. Drug overdose deaths.

  11. National Institute on Drug Abuse. Prescription opioid use is a risk factor for heroin use.

  12. Centers for Disease Control and Prevention. Overdose death rates.

  13. Dahlhamer J, Lucas J, Zelaya, C, et al. Prevalence of chronic pain and high-impact chronic pain among adults — United States, 2016. MMWR Morb Mortal Wkly Rep 2018;67:1001-1006. doi:10.15585/mmwr.mm6736a2

Additional Reading

By Kendra Cherry
Kendra Cherry, MS, is the author of the "Everything Psychology Book (2nd Edition)" and has written thousands of articles on diverse psychology topics. Kendra holds a Master of Science degree in education from Boise State University with a primary research interest in educational psychology and a Bachelor of Science in psychology from Idaho State University with additional coursework in substance use and case management.