Introduction: opioid-induced constipation.

Abstract

Although opium has been used to treat pain for thousands of years, it was not until the early 1800s when morphine, the principal alkaloid and most powerful ingredient of opium, was isolated by the German pharmacist Friedrich Sertyrner that pharmacological production of opioids became possible. The discovery of morphine was soon followed by isolation of opium's other active ingredients, including codeine and papaverine, and more recently the synthesis of even more potent opioids. Although opioids are effective for chronic pain and are generally recommended for patients who have failed nonopioid therapies, they are associated with untoward effects, including sedation, respiratory depression, euphoria, abuse, and a number of gastrointestinal side effects. The most common gastrointestinal side effects include nausea, vomiting, reflux, and constipation. Opioid-induced constipation (OIC), the focus of this supplement in the American Journal of Gastroenterology, is the most common side effect of opioids, affecting approximately 40% of patients with noncancer pain who use this treatment. Unlike many of the other side effects from opioids, OIC does not tend to improve with prolonged use. Opiates cause constipation by hindering colonic transit and decreasing intestinal and colonic secretion. The symptoms of OIC are not limited to bowel frequency and consistency but also include excessive straining, incomplete evacuation, and abdominal symptoms such as discomfort and bloating. Together these symptoms can have a negative impact on a patient's quality of life.