A peripheral opioid antagonist for treating urinary retention induced by opioids: A case report.

Abstract

Urinary retention is a poorly studied opioid-related adverse effect. There is a paucity of data regarding the treatment of such disturbance in patients with advanced cancer receiving opioids. A young man, without comorbidities, was receiving 30 mg/day of oxycodone for abdominal pain due to pancreatic cancer, unsuccessfully. He also complained of severe urinary retention that developed after initiation of opioid therapy. Methadone therapy was effective on pain intensity, but bladder dysfunction persisted. Only anedoctal experience exists for opioid-induced urinary retention. The options included alpha-receptor blockers and <b>flavoxate</b>, which are symptomatic drugs, not addressed to the possible mechanism. The use of a peripheral opioid antagonist was planned, according to the presumed mechanism of urinary retention. Thus, naldemedine 200 mcg was prescribed for relieving urinary retention. The day after starting naldemedine, urinary retention completely reversed and pain was well-controlled. The rational of using naldemedine was based on the component of opioid-induced urinary retention due to involvement of peripheral receptors in the bladder and sphincter. In this case report, the effect of the peripheral opioid antagonist was prompt and long-lasting. Future studies of this neglected adverse effect of opioids should be performed to confirm this observation.