In 2013, an estimated 207 million opioid prescriptions were dispensed by retail pharmacies in the U.S. (https://www.drugabuse. gov/about-nida/legislative-activities/testimony-to-congress/2016/ americas-addiction-to-opioids-heroin-prescription-drug-abuse). While opioids are highly efficacious for the treatment of acute and chronic pain, they may cause a number of significant side effects. One of the most commonly reported side effects of opioid use is opioidinduced constipation (OIC). According to recent studies, 41-47% of patients using opioids for chronic pain experience significant OIC. In patients on chronic opioid therapy, the degree of OIC can be quite severe and even debilitating.
A number of therapeutic interventions are currently available to treat OIC with varying degrees of efficacy. Treatment for OIC may include over-the-counter (OTC) options such as stimulant laxatives, stool softeners and osmotic laxatives, as well as prescription drugs that antagonize peripheral μ-opioid receptors, and directly stimulate intestinal secretions and motility. The various treatment options will be discussed below with emphasis on their mechanism of action, efficacy, and potential side-effects.