Methylnaltrexone for Refractory Opioid-Induced Constipation in Hospitalized Cancer Patients—A Highly Effective Treatment (F415A)

Abstract

1.Describe the overall efficacy of methylnaltrexone when prescribed to hospitalized cancer patients for opioid-induced constipation.2.Recognize the difference in response rates between patients receiving lower doses of opioids and those receiving higher doses of opioids. Methylnaltrexone is a peripherally acting mu-opioid receptor antagonist that has been studied in cancer and non-cancer patients with opioid-induced constipation (OIC), but only in the outpatient setting. For hospitalized patients with cancer pain and laxative-refractory OIC, its effectiveness is unknown. Describe the efficacy of methylnaltrexone on OIC in the inpatient setting. We performed a single-center, retrospective chart review of all hospitalized, adult patients with a cancer diagnosis who received methylnaltrexone from the palliative medicine team at our institution between January 1, 2012, and July 1, 2019. We identified 365 patients. The mean age was 57, 54% were male, and 82% were white. 360 patients (99%) received the 6 mg dose. The median oral morphine equivalent (OME) was 144 mg (range 0-4320mg). 58% (95% CI, 53-63%) had a bowel movement (BM) within 24 hours, and 73% (95% CI, 69-78%) had a BM within 48 hours. Higher OME was associated with successful BM. Patients with <150 OME had a response rate of 38% and patients with >150 OME had a response rate of 95% (p <0.001). Patients who received osmotic and stimulant laxatives prior to methylnaltrexone experienced no difference in response rates, although those who took stool softeners prior to receiving methylnaltrexone had a higher response rate. Methylnaltrexone is an effective treatment for OIC in the inpatient setting, especially for patients taking >150 OME.