The most appropriate management of this patient is to add a scheduled stimulant laxative, such as senna. Opioid-induced constipation is nearly universal in patients on regularly scheduled opioid therapy. Unlike other side effects of opioid medications such as nausea or somnolence, tolerance to constipation does not develop over time. Therefore, all patients on scheduled opioids should be prescribed a scheduled stimulant laxative, such as senna or bisacodyl. If this therapy does not adequately control opioid-associated constipation, osmotic agents (polyethylene glycol powder, sorbitol, lactulose) can be added.

Stool softeners, such as docusate, are inadequate to manage opioid-induced constipation when given alone. However, stool softeners may be given along with a stimulant laxative to further aid in preventing constipation in patients on chronic opioid therapy. Similarly, fiber supplements or other bulking agents are ineffective in managing opioid-induced constipation.

Methylnaltrexone, an injectable peripheral opioid antagonist, is very effective in treating opioid-induced constipation without adversely affecting analgesia. However, it is reserved for opioid-induced constipation that has failed to respond to an aggressive laxative regimen, and as such, it is considered second-line therapy. This patient has not had a trial of aggressive laxative therapy; therefore, methylnaltrexone is not yet indicated.