Reviewed by: HU Medical Review Board | Last reviewed: March 2023


Pain is one of the most common symptoms of endometriosis. Naturally, endo warriors in pain want relief and use a combination of home remedies, over-the-counter drugs, or prescriptions.

Opioids are a powerful class of drugs used to treat pain. However, opioids work best for short-term (acute) pain that happens after surgery or an injury. Opioids are not effective for long-term, or chronic pain, like that experienced with endometriosis. Other kinds of pain relief work better for endometriosis pain.1

How do opioids work?

Opioids attach to what are called opioid receptor proteins. Opioid receptors are found on nerve cells in the brain, spinal cord, gut, and other organs. Once latched onto the nerve cell and its receptors, opioids block pain messages being sent from the body to the brain.2,3

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Opioids also increase dopamine levels. Dopamine is a chemical in the body that makes us feel happy. Overall, opioids work on the areas of the brain involved in feeling “high,” euphoria, and pleasure.

What are the active ingredients in opioids?

Prescription opioids are a group of drugs that mimic the effects of the opium (poppy) plant. Some prescription opioids are made from the plant, and some are made in a lab. The active ingredients in an opioid vary based on the drug. Common opioid active ingredients include:2,3

  • Hydrocodone with acetaminophen (Vicodin)
  • Oxycodone ER (Oxycontin)
  • Oxycodone (Roxicodone)
  • Oxycodone with acetaminophen (Percocet)
  • Morphine
  • Oxymorphone (Opana)
  • Codeine
  • Fentanyl

All of these active ingredients work in a similar way. Their chemical properties, the way they are made, and how long it takes the drugs to work can be different.

What are the possible side effects of opioids?

Opioids come with many side effects, some serious. Side effects can vary depending on the specific drug you are taking. They may include:2

  • Drowsiness
  • Confusion
  • Nausea
  • Constipation
  • Making pain feel worse over time
  • Addiction or dependence
  • Trouble breathing, including respiratory failure and even death

These are not all the possible side effects of opioids. Talk to your doctor about what to expect if taking an opioid for the first time. Call your doctor if you feel any changes that concern you.

Things to know about prescription opioids

You may have been prescribed opioids for endometrial pain in the past. Now, doctors are prescribing fewer opioids. After an explosion of prescriptions in the early 2000s, doctors learned opioids are not effective for long-term or chronic pain. These drugs also come with a serious risk of dependence or addiction.2,3

One study found endo warriors who take opioids face much higher annual health costs. Those using opioids spent nearly $30,000 a year more for medical care versus about $18,500 for those using other pain relief. Higher costs began within 1 year of filling an opioid prescription. Costs increased the more opioid was taken.1

If you are prescribed an opioid for endo pain, be sure to tell your doctor about all your health conditions. Opioids can affect how well other drugs work. Discuss any prescription drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.