Opioids With or Without Olanzapine in Treating Patients With Moderate to Severe Cancer Pain

DISEASE CHARACTERISTICS:

• Moderate to severe cancer pain
• Pain score ≥ 7/10 (0-10 numeric pain rating scale)
• Requires strong opioids (step 3) for pain control or are already on stable doses of step 3 opioids
• Opioid induced cognitive dysfunction or cognitive impairment, defined as cognitive disorder not otherwise specified according to Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) allowed
• No nonmalignant pain
• If patient has both malignant and nonmalignant pain, eligibility will be determined by the predominant site of pain

PATIENT CHARACTERISTICS:

• Life expectancy ≥ 3 months
• Normal renal function
• Not pregnant or nursing
• Negative pregnancy test
• Must have a telephone
• Able to complete patient questionnaires alone or with assistance
• No delirium
• No hepatic dysfunction
• No nursing home patients
• No intractable nausea or vomiting
• No true allergy or intolerance to opioids
• No gastrointestinal pathology that influences absorption of opioids
• No drug seeking behavior or recent substance abuse history
• No major depression
• No respiratory compromise
• No evidence of severe or uncontrolled systemic disease (e.g., unstable or uncompensated respiratory, cardiac, hepatic, or renal disease)
• No evidence of any other significant clinical disorder or laboratory finding that makes it undesirable for the patient to participate in the study

PRIOR CONCURRENT THERAPY:

• More than 1 month since prior radiotherapy, chemotherapy, or radionuclides
• More than 1 month since prior bisphosphonates
• No prior surgery that influences absorption of opioids
• No concurrent therapeutic procedures or treatments that influence pain
• No concurrent active radiation or antineoplastic therapies
• No concurrent retroviral therapies
• No concurrent drugs that interfere with CYP34A, CYP1A2, or CYP2D6
• No concurrent drugs that interfere with morphine metabolism
• No concurrent medications that will influence the disposition of morphine or methadone
• No other concurrent antiemetics, antianxiety, or neuroleptic agents