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Opioids

Opioids are a class of drugs that manage moderate to severe pain. There are prescription and nonprescription versions available. They have high addiction potential and could lead to opioid use disorder and overdose. It’s important to talk with your provider about the risks and benefits before taking opioids.

What Are Opioids?

Opioids, sometimes called narcotics, are a class of drugs that may reduce moderate to severe pain. Some opioids are naturally produced, while others are human-made.

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Opioids interact with nerve cells to reduce pain signals from reaching your brain. This prevents you from feeling the sensation of pain while the drug is in your body. This drug can also create a sense of euphoria or a strong feeling of happiness. It does this by triggering your brain’s reward system.

Because of the way opioids make you feel, there’s a high risk of developing an addiction. While you may want to stop taking an opioid, your brain and reward system want more of it. You may feel psychologically and physically dependent on the drug. You may build your tolerance and seek out more of the drug to get the same effect. This could lead to a life-threatening opioid overdose.

Because of the high addiction potential, healthcare providers will closely monitor you if you need to take prescription opioids to prevent opioid use disorder and overdose. They’ll help transition you off opioids to reduce the severity of withdrawal symptoms.

Types of opioids

Some of the most common types include:

There are over 100 different types of opioids. These can be grouped into three categories:

  • Natural: Substances made from the seed pods of the poppy plant. These are also called opiates (morphine, codeine).
  • Semi-synthetic: Substances made in a laboratory using natural opioids (heroin, hydrocodone).
  • Synthetic: Substances made in a laboratory without using any natural ingredients (fentanyl).

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Medical uses for opioids

Your healthcare provider may prescribe an opioid to help you manage different types of severe pain, including:

The U.S. Food and Drug Administration (FDA) approves the use of some opioids to treat intense coughing and chronic diarrhea.

Prescription opioids come in various forms, including:

  • Tablets and capsules (oral pills)
  • Oral solutions
  • Injected solutions
  • Suppositories

How do opioids work?

Opioids work by binding to opioid receptors in your body. These are in your central and peripheral nervous systems. They’re also in your gastrointestinal (GI) tract. Opioid receptors regulate many body functions, including:

  • Breathing (respiration)
  • Gastrointestinal functions
  • Mood
  • Pain
  • Reward
  • Stress

What other medications and substances can interact with opioid drugs?

Opioids may negatively interact with other medications, supplements or substances in your body. Interactions may be harmful. This is why it’s important to be honest with your provider about what you’re taking.

Medications and substances that may interact with prescribed opioid medications include:

What are the side effects of opioids?

Common side effects of opioids include:

  • Drowsiness
  • Dizziness
  • Nausea and vomiting
  • Constipation
  • Opioid-induced hyperalgesia (severe or excessive pain)

Opioid use disorder is a complication of taking opioids. It can lead to serious and potentially life-threatening side effects, including:

  • Overdose: This is a medical emergency that affects the part of your brain that regulates breathing. Common symptoms include shallow breathing, loss of consciousness and a slow heartbeat.
  • Physical dependence: You experience unpleasant symptoms like cravings, sweating and anxiety when you stop or lower the dosage of an opioid.
  • Respiratory depression: You aren’t able to get enough air into your lungs. Breathing becomes shallow and carbon dioxide can build up in your blood.
  • Tolerance: After taking opioids for a long time, you require increased dosages to experience the same effect of pain relief.

If you or a loved one is at risk of an opioid overdose, you may consider carrying naloxone. This is an often life-saving opioid blocking medication. You can get it without a prescription at local pharmacies. Training is available so you can learn how to use naloxone safely.

What are the long-term effects of opioids?

Long-term side effects from opioid use may include:

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How long do opioids stay in your system?

According to the FDA, opioids, like heroin and methadone, may stay in your body for one to three days. But the exact amount of time varies based on many factors, including:

  • The health of your liver and kidneys
  • The type of opioid
  • Whether you’ve taken other substances with opioids
  • Your age
  • Your body mass and weight
  • Your sex

The exact amount of time may vary based on how long you’ve been taking opioids, the dosage and how well your metabolism is working.

A note from Cleveland Clinic

Opioids are very powerful drugs. You may need to take them, especially after a serious accident or if you’re living with chronic pain.

Due to its high addiction potential, your healthcare provider will monitor how effective this medication is while you’re taking it. Talk with your provider as soon as possible if you feel like you’re dependent on opioids or if they’re not working to manage your symptoms.

In some cases, opioids aren’t prescribed by a healthcare provider, and they’re available in other, non-legal forms. Using these substances increases your risk of overdose. You can stay safe by carrying naloxone. Know that you can always talk to a healthcare provider or reach out to the free, confidential National Helpline (SAMHSA at 1.800.662.HELP) when you’re ready.

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Care at Cleveland Clinic

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Medically Reviewed

Last reviewed on 07/22/2025.

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