RATIONALE: Naloxone may be effective in treating constipation that may be caused by opioid
pain medications such as morphine.
PURPOSE: Phase III trial to determine the effectiveness of naloxone in relieving constiption
in patients who are receiving opioids for chronic pain.
OBJECTIVES: I. Assess the long-term safety and efficacy of oral naloxone in treating
opioid-induced constipation in patients with chronic malignant or non-malignant pain.
OUTLINE: This is a multicenter study. Patients receive oral naloxone twice daily. Each
patient receives an escalating dose until the minimum effective dose or the maximum dose
allowed is reached. The minimum effective dose is defined as the dose at which a patient has
at least 4 bowel movements within 7 days. Patients receive the minimum effective dose for 7
days and then continue long-term treatment for a maximum of 72 weeks. Patients receiving the
maximum dose allowed with fewer than 4 bowel movements per week will discontinue study
PROJECTED ACCRUAL: Approximately 600 patients will be accrued for this study.
DISEASE CHARACTERISTICS: Moderate to severe opioid-induced constipation Previously
enrolled on protocols NAL-0396, NAL-0397, and/or NAL-0398 OR Low frequency of bowel
movements, defined as fewer than 3 per week during the past 2 weeks, AND either of the
following: Score of "some", "quite a bit", or "very much" on the constipation distress
scale Laxative or enema dependence Daily opioid intake equivalent to at least 30 mg of
oral morphine for chronic pain of malignant or non-malignant origin Stable dose of opioid
analgesic agent for at least 2 weeks No score of "excruciating" on verbal pain scale No
history of partial or complete bowel obstruction No constipation secondary to factors
other than opioids (e.g., autonomic neuropathy or intra-abdominal adhesions)
PATIENT CHARACTERISTICS: Age: Over 18 Performance status: Not specified Life expectancy:
Not specified Hematopoietic: Not specified Hepatic: Not specified Renal: Potassium normal
Other: No uncontrolled endocrinopathy or diabetes No psychiatric disorder or
encephalopathy that would preclude study No clinically significant medical conditions that
would preclude study Not pregnant or nursing Negative pregnancy test Fertile patients must
use effective contraception
PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: Concurrent
chemotherapy allowed provided patient has completed at least 1 course prior to study
Endocrine therapy: Concurrent hormonal therapy allowed provided dosage is stable for at
least 2 weeks prior to study Radiotherapy: No concurrent palliative radiotherapy to spine,
abdomen, or pelvic area Surgery: Not specified Other: At least 30 days since other