Compassionate Use Study of Methylnaltrexone

Inclusion Criteria

• Advanced medical illness (that is; terminal illness, such as incurable cancer or end stage aqcuired immunodeficiency syndrome [AIDS]) with a life expectancy of one to six months.
• On an opioid regimen for the control of pain/discomfort for at least seven days.
• Has opioid-induced constipation.
• Stable vital signs and systolic blood pressure greater than or equal to (>=) 85 millimeters of mercury (mmHg), and diastolic blood pressure >=45 mmHg (Supine or sitting).
• Females of childbearing potential must have a negative pregnancy test (serum or urine).
• On a laxative regimen (for example, stool softener and SENNA or equivalent) for at least 3 days prior to treatment. Participants who have discontinued laxatives due to intolerability or lack of efficacy are also eligible.

Exclusion Criteria

• Participants with known hypersensitivity to methylnaltrexone, naltrexone or naloxone.
• Participants who received any investigational new drug (experimental) except for methylnaltrexone in the previous 30 days.
• Participants who are constipated with a disease process suggestive of gastrointestinal obstruction, impaction or diagnosed with a current abdominal pathologic process which may represent a non-opioid cause of bowel dysfunction.
• Participants who are constipated and have active, clinically significant diverticulitis.
• Participants with a surgically acute abdomen.
• Participants being treated with opioids for diarrhea, dyspnea, cough, pulmonary edema, or congestive heart failure.
• Individuals with a known drug addiction.
• Females who are pregnant or nursing.