Opioids are effective for treating and managing pain, but using them frequently can lead to constipation. This can affect a person's comfort, health, and quality of life.
Doctors often prescribe opioids for pain relief when people have these or other conditions that cause chronic pain, such as fibromyalgia. Opioid use can be a cause of constipation, although there may be other reasons, too.
Since opioids are a common cause of constipation, a doctor will often suggest some lifestyle changes or offer additional medications, such as laxatives, at the same time as prescribing the opioids.
Find out some ways to reduce opioid-induced constipation (OIC), including home and natural remedies and pharmaceutical options.
Doctors normally recommend some lifestyle changes before prescribing or suggesting medications for OIC.
Ways to reduce or prevent the symptoms of constipation include:
- consuming more dietary fiber, including fruits, vegetables, and wholegrains
- increasing fluid intake, especially water
- if possible, doing more exercise or physical activity
- making time and privacy for toileting
Sometimes lifestyle changes are not possible, however, or they do not make enough difference and the problem continues. In this case, the doctor may recommend medications.
Some people will need to use additional medicines along with the opioid pain-relief drugs that are causing the constipation.
Often, a doctor will prescribe laxative or cathartic medication — both of which can help reduce constipation — at the same time as the opioid medication.
In this way, treatment for the constipation begins immediately.
Cathartics accelerate defecation, while laxatives make it easier. Some medicines work as both laxatives and cathartics.
However, because laxatives do not address the underlying opioid action that causes the constipation, they often do not work very well.
To treat OIC, doctors may prescribe:
Osmotic laxatives: These raise the amount of water in the gut, increasing bulk and softening stools.
Emollient or lubricant cathartics: These soften and lubricate stools.
Bulk cathartics: These increase bulk and soften stools.
Stimulant cathartics: These directly counter the effect of the opioid medications by increasing intestinal movement and helping the gut to push the stools along.
Prostaglandins or prokinetic drugs: These change the way the intestines absorb water and electrolytes, and they increase the weight and frequency of stools while reducing the amount of time it takes for stool to pass through.
Other options are:
- Changing to pain relief medication that is not opioid-based, although this may not be helpful for people who need strong pain relief.
- Using medicines that reverse OIC by blocking the effects of opioids on the bowel.
If the person has a bowel obstruction, they should not take laxatives by mouth, as this can lead to a buildup of matter above the blockage.
However, a stool-softening agent may help if there is a partial blockage, especially if this is due to constipation.
If medications do not work, or if there is a blockage, a physician may recommend a rectal intervention.
- glycerine or other suppositories
- an enema, for example, a stimulant enema
- rectal or colonic irrigation with normal saline solution
- manual evacuation
Gentle rectal measures can sometimes be effective in emptying the rectum and lower colon.
If rectal laxatives do not work, a doctor may try rectal irrigation. If nothing else works, it will be necessary to carry out a manual evacuation.
Some drug treatments aim to provide both pain relief and a reduction in constipation, but in different ways.
Methylnaltrexone (Relistor) helps restore bowel function in people who have advanced illness and receive opioids for pain relief.
This drug specifically targets OIC.
The doctor will give the person a dose of methylnaltrexone as an injection under the skin.
When a person takes it together with an opioid, it can stop the opioid from binding to receptor proteins in the gut.
In this way, it reduces the opioid's constipating effects and encourages defecation, but it does not reduce the pain-relieving effect of the opioid.
Relistor can also have some adverse effects. The manufacturers caution that people should not use it if they have a bowel blockage and that it can lead to intestinal tears.
Some people may also experience effects resembling withdrawal symptoms from opioids, such as sweating, chills, diarrhea, anxiety, and yawning. Anyone who experiences these side effects should speak to a doctor.
Newer medications, such as naloxone (Targin), can relieve severe pain and long-term pain without causing constipation.
These tablets combine prolonged release oxycodone — an opioid that treats pain — and prolonged release naloxone, a compound that can reduce the opioid's effects on the gut.
Constipation can be a problem for people who need to use opioids for long-term pain relief.
However, eating enough fiber and consuming plenty of fluid can help, and a doctor can often suggest additional ways to prevent or relieve constipation if it does occur.