Constipation is a common and often unexpected side effect of opioids for people living with opioid use disorder (OUD). Being constipated means it’s hard to have a bowel movement (poop). When constipation is caused by opioid use, it’s called opioid-induced constipation (OIC). Many people who take opioids experience some level of constipation.

If you take opioids, constipation can sneak up on you. OIC is not just uncomfortable — it can affect daily life. Keep reading to learn about the common signs of OIC and the treatments that can help.

Why Do Opioids Cause Constipation?

Opioids work by binding to proteins called opioid receptors. When opioids bind to opioid receptors in the central nervous system (brain and spinal cord), they can relieve pain and create feelings of pleasure. But these opioid receptors are also found in other parts of the body, including the gastrointestinal (digestive) tract.

When opioids bind to opioid receptors in your gastrointestinal tract, they slow down the natural movement of the intestines (called peristalsis). Peristalsis pushes stool through the bowels. When this movement slows, stool stays in the intestines longer, so more water is absorbed and the stool becomes hard and dry.

When opioids bind to opioid receptors in your gastrointestinal tract, they slow down the natural movement of the intestines (called peristalsis).

Opioids also make it harder to tell when your rectum (the last part of the colon) is full. That means you may not notice the urge to poop. At the same time, opioids can tighten the muscles around the anus (the end of the rectum, where stool leaves the body), making it more difficult to poop. This is why constipation is one of the most common side effects of opioids.

5 Signs of Opioid-Induced Constipation

OIC may show up in different ways. Some people notice signs of OIC right away when they start taking an opioid. For others, symptoms of OIC develop slowly and lead to chronic constipation. Either way, OIC is a change from the bowel habits you had before starting an opioid.

You don’t need to have all of these signs to have OIC. Having two or more within three months may be a warning. These signs can help you spot OIC early and know when to talk with your healthcare provider about treatment options.

1. You Have Fewer Than Three Bowel Movements a Week

Constipation means fewer than three bowel movements per week. This is also true for OIC. Normal bowel patterns are different for everyone, ranging from three times a week to three times a day. With OIC, you may notice your bowel movements become less frequent than they were before you started taking opioids.

When you’re taking an opioid, your stool moves more slowly through your intestines, and it’s harder to feel the urge to have a bowel movement. That means bowel movements without the help of medications (called spontaneous bowel movements) may happen less often.

2. Your Stool Is Hard or Lumpy

Another common sign of OIC is having hard or lumpy stools. This happens because opioids slow the movement of your stool through your intestines, increasing how much water your body absorbs. This creates dry, hard stool that’s painful and difficult to pass.

Healthcare providers use the Bristol Stool Form Scale to classify stool into seven types, ranging from watery diarrhea to very hard stool. In OIC, at least 1 in 4 stools may look like small pebbles (type 1) or a lumpy log (type 2). Diarrhea (type 6 or type 7) is uncommon in OIC unless laxatives are used.

3. You Have To Strain To Have a Bowel Movement

When your stools are hard and difficult to pass, you might feel like you have to push hard to have a bowel movement. People with OIC may need to strain during at least 1 in 4 bowel movements.

With opioid-induced constipation, you may need to strain during at least 1 in 4 bowel movements.

4. You Still Feel Like You Have To Go Right After a Bowel Movement

OIC can make it feel like your bowels didn’t empty all the way. Even after a bowel movement, you might still feel pressure or the urge to go again. If this happens during at least 1 in 4 bowel movements, this may be a sign of OIC.

5. Constipation Doesn’t Improve When You Change Your Diet

Constipation is very common and can often be managed with dietary and lifestyle changes at home. A high-fiber diet is a common treatment for constipation. Fiber adds bulk to the stool and helps the stool hold water, which makes it easier to pass.

Eating more fiber may not help with the treatment of OIC. Fiber adds bulk to stool but does not change how fast stool moves through the intestines. In OIC, the main problem is slower movement in the intestines, so even bulky stools can be hard to pass.

When To Seek Medical Attention for Constipation

When constipation is severe, it can cause serious complications. If you have any of the following symptoms, seek medical attention right away:

• Severe abdominal pain
• Vomiting
• Black stools or red blood in your stool
• Blood on your toilet paper
• Sudden changes in your bowel habits

Talk to your healthcare provider if constipation lasts more than three weeks, if symptoms make daily life harder, or if you’ve lost weight without trying.

Treating Opioid-Induced Constipation

Once OIC develops, it can be difficult to manage. Managing OIC usually involves a combination of lifestyle changes and medications.

Opioid Use Disorder Treatment

For people living with OUD, treating the disorder itself can ease constipation while also supporting recovery.

Treatment for OUD often includes medications for opioid use disorder (MOUD) such as buprenorphine (Brixadi) or methadone hydrochloride (Methadose). These medications help reduce cravings and withdrawal symptoms, making recovery safer and more manageable. Over time, MOUD may reduce opioid use, which can also improve side effects like constipation in people with OUD.

Gradually tapering off opioids under medical supervision can help the digestive system return to normal. Always follow the instructions of your healthcare provider. Stopping opioids suddenly is not safe and can cause withdrawal symptoms.

Gradually tapering off opioids under medical supervision can help the digestive system return to normal.

Treatment for OUD goes beyond medication. Counseling, peer support, and behavioral therapy are also key. These approaches address the physical, emotional, and social aspects of OUD while helping improve your quality of life.

Talk to your healthcare provider about treatment options for OUD and how these treatments may support both your recovery and your digestive health.

Lifestyle Changes

Healthy lifestyle habits are an important part of the prevention and treatment of OIC. Important lifestyle changes for OIC include:

• Increasing fluid intake
• Increasing fiber intake
• Avoiding foods high in fat
• Getting regular exercise
• Going to the toilet as soon as you feel the urge to have a bowel movement

If you add more fiber to your diet, be aware that it may cause side effects like bloating and flatulence (gas). This happens because opioids slow the movement of fiber through your digestive system.

Most people with OIC should avoid bulk-forming fiber products like psyllium. Too much of these products can make constipation worse and even cause a bowel obstruction (blockage). Talk to your healthcare provider about safe ways to add fiber to your diet.

Medications

Laxative medications are usually the first medicines recommended for OIC. Different types of laxatives work in different ways to improve stool frequency and consistency, making it easier to have a bowel movement.

Over-the-Counter Laxatives

Over-the-counter (OTC) laxatives that may help with OIC include:

• Stimulant laxatives — These activate nerves that control the muscles in the intestines, helping stool move. Examples include senna and bisacodyl.
• Osmotic laxatives — These pull water into the intestines to soften stool. Examples include polyethylene glycol, magnesium hydroxide, and magnesium citrate.
• Lubricant laxatives — These coat the stool and the intestinal lining so stool moves more smoothly. Mineral oil is an example.

Even though these laxatives are available without a prescription, talk to your healthcare provider before using them for OIC.

Prescription Laxatives

If OTC laxatives don’t work, your healthcare provider may suggest prescription medications. Peripherally acting mu-opioid receptor antagonists (PAMORAs) are medications approved to treat OIC. They block the effect of opioids in the gastrointestinal tract. Examples include methylnaltrexone, ​​naloxegol, and naldemedine.

Other prescription laxatives that may help treat OIC include lubiprostone and prucalopride. Lubiprostone is FDA-approved for OIC for adults with long-term pain that isn’t related to cancer, while prucalopride isn’t specifically approved for OIC.

Your healthcare provider can help you decide which lifestyle changes and medications are best for preventing and treating OIC.

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