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Opioid Induced Constipation (OIC)

Opioid induced constipation, or OIC, is a condition that affects how your digestive system works. Opioids are strong pain medicines that slow bowel movements, causing fewer or more difficulty having a bowel movement than normal. Hence the term “opioid-induced” constipation.

Your healthcare provider might prescribe opioids if you have a condition that causes moderate to severe pain. Healthcare providers may prescribe opioids for pain from a procedure, such as surgery or dental work; an injury or accident; a chronic, or long-lasting, condition that causes pain; cancer or illness at the end of life. While opioids can treat pain effectively, they have known side effects. Between 50 and 80 percent of people who take opioid medicines have constipation.

OIC is the most common side effect that opioids have on your digestive system; however, there are others. Opioid-induced bowel dysfunction, or OIBD, is the medical term for the effects on the digestive system caused by opioids. Besides constipation, other symptoms of OIBD include heartburn, nausea, vomiting, bloating, as well as chronic, or long-lasting, abdominal pain.

How is opioid-induced constipation diagnosed?

To diagnose OIC, your healthcare provider will ask questions about your symptoms, the medicines you take, and more. They will also examine you. This includes an examination of your rectum, where bowel movements are stored before leaving the body. You might give a small sample of blood to test for conditions that could cause constipation.

Learn more about how to talk with your healthcare provider

Are there diagnostic tests that confirm opioid-induced constipation?

Specific tests are not the main way to diagnose OIC. Constipation is very common when you take opioid medicines. So, if you start taking them, start taking a different one, or increase your dose and become constipated, it is very likely opioids are the cause. However, your healthcare provider may request an X-ray to see if waste has built up in your body, and if so, how much. If your healthcare provider is concerned you may have a digestive problem besides constipation, then they might perform a colonoscopy which is an examination of your digestive system with a thin, lighted tube inserted into the rectum.

Learn more about GI Motility Tests

Which bowel diseases can cause constipation?

Bowel diseases that can cause constipation include (but are not limited to) irritable bowel syndrome (IBS), bowel obstruction (something blocking the bowel), or cancer. Other non-gastrointestinal conditions that can cause constipation include low thyroid hormone levels, diabetes, Parkinson’s disease, multiple sclerosis and more. You could also have dyssynergic defecation, which is difficulty coordinating your muscles when having a bowel movement. Your healthcare provider will check for these and other conditions if necessary.

Your healthcare provider will check for other symptoms of these diseases when they examine and talk to you. They might ask you to see a specialist to learn more. If you do not have a specific disease, opioids are very likely to be the cause of your constipation.

What should I ask my healthcare provider about diagnosing opioid-induced constipation?

Make sure your healthcare provider knows about all the medicines you currently take, ask them which ones may cause constipation, and how they can determine if a particular medicine is the cause of your constipation. You can also ask if they are concerned about other conditions and if you need specific tests to learn why you have constipation.

Talking with your healthcare provider about your concerns is the best way to stay healthy and comfortable while getting the symptom relief you need.

What are the symptoms of opioid induced constipation (OIC)?

The main symptom of OIC is a change in your usual bowel habits after you start taking opioid medicines.

Changes may include:

  • Less frequent bowel movements
  • Difficulty having bowel movements
  • Feeling like you cannot empty everything completely
  • Very firm or hard bowel movements

Besides constipation, opioid medicines can cause other side effects. For example, you may have side effects related to your nervous system. These can include nausea and vomiting, slow breathing, feeling very sleepy, and feeling either “high” or depressed. You might also have worsening abdominal pain.

What causes OIC?

Your body and essentially your muscles and nerves have areas called “receptors” in the digestive system. When you take opioid medicines, they activate these receptors and change the way your digestive system works. Opioid medicines slow down the normal movement of food and waste through your system. They also reduce the moisture that makes it easier to have bowel movements and tighten up the muscles that need to relax when you have a bowel movement.

OIC risk factors

Taking opioid medicines is the main risk factor for opioid-induced constipation. You can lower your risk of OIC, relieve symptoms, or both by talking with your healthcare provider and pharmacist before you start taking opioid medicines.

If I have opioid-induced constipation (OIC), can lifestyle changes help?

You might be able to manage your OIC with some lifestyle changes. These may include drinking more fluids, eating more foods with fiber, and becoming more active. Your healthcare provider might also give you medicine to take if you become constipated. Before you start taking opioids, ask your healthcare provider about ways to prevent constipation or treat it if you have it.

Today, there are several FDA approved medications opioid-induced constipation.  If lifestyle and simple laxatives don’t help, consult your healthcare provider for consideration of some of the new therapies.

Alarm Features of OIC

If you have certain symptoms, your healthcare provider will check for other conditions besides OIC. These symptoms can include:

  • Unexplained weight loss
  • Frequent fevers
  • Blood in your bowel movements
  • A low red blood cell count, called anemia
  • A history of colon cancer in your family

Learn more about alarm symptoms

What are the consequences of OIC?

Opioid-induced constipation can be so unpleasant that you stop taking the opioid medicines. But if they control your pain best, you might not get the pain relief that you need. In rare cases, OIC can cause serious health problems, including pain in the rectum, where bowel movements leave the body. It can also cause a blocked or torn bowel. This is serious and can be life-threatening. If constipation becomes severe, your healthcare provider may prescribe medications such as pills, enemas, or suppositories to relieve it.

How is Opioid-Induced Constipation (OIC) Managed and Treated?

There are different ways of managing and treating opioid induced constipation (OIC). Your healthcare provider will ask about your diet and lifestyle and recommend non-prescription medicines. If these do not work, they might prescribe a different pain medicine or a medicine to treat OIC.


Your healthcare provider should make sure opioid medicines are the best choice for treating your pain when they prescribe them and place you on the lowest dose needed to control your pain. A healthcare provider specializing in pain management is a vital part of your health care team. They can work with your healthcare provider to find ways to prevent OIC and other side effects or lower the risk of OIC.

Medications for OIC:

Non-prescription laxatives

Taking non-prescription laxative medicines may help you manage opioid induced constipation. These medicines work in different ways to make it easier to have a bowel movement. They can stimulate the nerves in your digestive system, soften the waste, or make it bulkier.

You might need to try different types of laxatives or take more than one. For example, you can take a type of laxative called a “stool softener” that makes your stool easier to pass. Or you can take a type called a “stimulant laxative” that makes the nerves in your digestive system more active and sensitive. This can get your digestive system moving again. Your healthcare provider may recommend that you take both types or a different type of laxative.

Polyethylene glycol is another type that may help increase the amount of water in the intestinal tract to stimulate bowel movements. Your healthcare provider can help you decide which laxatives work best and how much you will need to take.

Prescription medicines

If laxatives do not help your OIC, you may want to speak with your healthcare provider about prescription medicines.

  • Lubiprostone (Amitiza®)
    Lubiprostone works through the activation of chloride channels in the bowel. This leads to increased bowel movement frequency. It is currently FDA approved specifically for use in women. This is due to the limited number of men that were enrolled in the initial trials. This drug has proven to be effective in men as well. Common adverse events include nausea and diarrhea. Lubiprostone is also FDA approved for the treatment of opioid induced constipation (OIC) in people with chronic non-cancer pain related illnesses. It is also approved for those with chronic idiopathic constipation (CIC) and constipation predominant irritable bowel syndrome (IBS-C).
  • Methylnaltrexone bromide (Relistor®)
    Some medicines keep opioids from attaching to the receptors in your digestive system and slowing it down. These medicines are called “opioid antagonists.” They “fight” the normal action of the opioids in your intestines without affecting pain control. Methylnaltrexone bromide is FDA approved for the treatment of opioid-induced constipation in advanced-illness patients who are receiving palliative care when the response to usual laxative therapy has not been sufficient. Palliative care is care given to improve the quality of life of patients who have a serious or life-threatening disease, such as cancer. Palliative care is an approach to care that addresses the person, not just their disease.

Talking to Your Healthcare Provider About OIC

Tell your healthcare provider if you have constipation when taking opioid medicines. If one way of treating constipation does not work, ask what else you can try. This might include switching to a different pain medication. Your healthcare provider can help you find the best way to control pain and avoid constipation.

Want to learn more?

Treating opioid induced constipation

Visit You and Constipation to learn more about Opioid induced constipation or click on the button below to watch a short video about how to manage and treat OIC.

Adapted from IFFGD Publication #154, 155, 156 by IFFGD, edited by Satish Rao

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IFFGD is a nonprofit education and research organization. Our mission is to inform, assist, and support people affected by gastrointestinal disorders.

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