Treatment Options for Painkiller-Induced Constipation
Chronic pain is a widespread problem in the United States, affecting many Americans’ physical and mental health, work performance, and quality of life. When over-the-counter pain relievers like ibuprofen and acetaminophen don’t do the trick, physicians often turn to prescribing opioid analgesics, also known as narcotics, to ease pain.
Opioids were once reserved for short-term pain and cancer-related pain, but in the 1990s, a variety of long-acting opioids came to the market, leading to a dramatic increase in the long-term use of opioids for chronic, non-cancer related pain. While opioids provide needed relief to those suffering from chronic pain, they’re not a magic fix. These drugs come with a long list of side effects, as well as the risk of addiction and overdose.
Common side effects, like nausea, mental cloudiness, drowsiness and dizziness tend to go away with time. Unfortunately, the most common side effect, constipation, stays with patients for the duration of the treatment period. This frustrating issue can be so intolerable that patients would rather stop taking opioids than live with constipation.
My heart goes out to these patients, as I don’t want them to live in pain or have to deal with gastrointestinal (GI) problems. When patients ask me about opioid-induced constipation (OIC), I emphasize that there are treatment options available so they can get relief from pain while also easing OIC.
Causes of Opioid-Induced Constipation
Opioids work by attaching to and activating small proteins called receptors. Opioid receptors are present throughout many locations in the body. Which receptors are activated determines what effect the opioids will have.
For example, activation of opioid receptors in the spinal cord produces pain relief. Activation of the receptors deep inside the brain can create feelings of pleasure (which is one of the reasons people can become addicted to opioids). And activation of the receptors in the GI tract impairs the function of the entire digestive system, causing bloating, abdominal discomfort, reflux, loss of appetite, nausea, vomiting, and constipation.
Constipation is the most common GI complaint and affects up to 47% of patients on opioids. However, that number may be greater, as not all patients disclose the issue with their doctors. It’s so common, in fact, that I recommend beginning a preventive bowel regimen when starting opioid therapy.
Preventing and Treating Opioid-Induced Constipation
The initial bowel regimen may include increased fluid intake, increased dietary fiber or fiber supplements, stool softeners, and laxatives. Adding exercise to your routine can help, as well as reserving adequate time and privacy for bowel movements.
If the preventive regimen isn’t effective, I recommend different treatment options to my patients:
There are several types of laxatives available—bulk-forming laxatives, osmotic laxatives, and stimulant laxatives. Bulk forming laxatives include natural fiber and commercial fiber preparations like psyllium (Metamucil), methylcellulose (Citrucel), calcium polycarbophil (Fiber-Lax), and wheat dextrin (Benefiber). Some experts believe these laxatives are not as beneficial for treating OIC, because of the way they work, but the recent recommendations from leaders in pain medicine have included them in their treatment plan. It’s very important that patients taking these laxatives stay well hydrated and combine this therapy with exercise and dietary changes.
Osmotic laxatives are essentially sugars that the body doesn’t absorb—they stay inside the gut and increase the amount of water in the gut, relieving constipation. One osmotic laxative, polyethylene glycol (MiraLax, Glycolax), is generally preferred since it doesn’t cause gas or bloating and is available without a prescription in the U.S. Two osmotic laxatives, lactulose and sorbitol, can be prescribed by your doctor and may produce gas or bloating.
THIS CONTENT DOES NOT PROVIDE MEDICAL ADVICE. This content is provided for informational purposes and reflects the opinions of the author. It is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified healthcare professional regarding your health. If you think you may have a medical emergency, contact your doctor immediately or call 911.
Farshad Ahadian, MD, is the medical director of
UC San Diego Health’s Center for Pain Medicine and a board-certified
anesthesiologist. View his Healthgrades profile >