A Multicenter, Randomized, Double-Blind, Placebo-Controlled, Phase IIB Study of Oral Naloxone for the Treatment of Opioid-Induced Constipation in Patients With Chronic, Non-Malignant Pain or Malignant Pain

Inclusion Criteria

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
investigational drug