Background: Cancer patients often require feeding or venting gastrostomy-tubes (G-tubes) for enteral nutrition or symptom palliation. The administration of most extended-release (ER) opioids via the G-tube or orally followed by clamping of the venting G-tube is contraindicated. Oxymorphone immediate release (IR) may be useful because of its longer half-life compared to other IR opioids. We examined the use of oxymorphone IR administered every 8 hours in patients with G-tubes.
Methods: This was a retrospective chart review of 40 consecutive cancer patients with G-tubes who underwent opioid rotation (OR) to oxymorphone. Demographics, symptoms, morphine equivalent daily dose (MEDD), and oxymorphone dose were collected. Successful OR was defined as a 2-point or 30% reduction in pain score and continued use of oxymorphone at follow-up in outpatient setting, or discharge in inpatient setting. Opioid rotation ration (ORR) between MEDD and oxymorphone in patients with successful OR was calculated as MEDD before the OR divided by total oxymorphone dose/day at follow-up or discharge.
Results: The median age was 56 years, 57.5% were white, 68% male, 47.5% (n=19) had head and neck cancer, 90% had advanced disease, 67.5% (n=27) were inpatient, and 15% (n=6) had venting G-tubes. 25/40 (62.5%) patients had successful OR to oxymorphone. The median ORR from MEDD to oxymorphone was 3.5 (IQR, 3.1-4). There were no independent predictors for successful OR, and ORR did not significantly differ among various groups.
Conclusions: Oxymorphone IR can be used successfully in cancer patients with G-tubes using an ORR of 3.5 to calculate dose from MEDD.
Keywords: Opioid rotation (OR); bowel obstruction; cancer; gastrostomy tubes; oxymorphone; pain.