Ondansetron in Treating Patients With Advanced Cancer and Chronic Nausea and Vomiting Not Caused by Cancer Treatment

DISEASE CHARACTERISTICS: Diagnosis of incurable cancer with chronic nausea and vomiting lasting at least 1 week that is not due to antineoplastic therapy (i.e., chemotherapy, radiotherapy, immunotherapy, biologic therapy) Nausea not adequately controlled by standard antiemetics PATIENT CHARACTERISTICS: Cardiovascular: No uncontrolled hypertension Other: Not pregnant or nursing Able to take oral medication (feeding tube allowed) Able to swallow own saliva No prior phenylketonuria No known allergy or intolerance to 5-HT3 receptor antagonists No bowel obstruction PRIOR CONCURRENT THERAPY: Biologic therapy: See Disease Characteristics Chemotherapy: See Disease Characteristics At least 2 weeks since prior cytotoxic systemic therapy No concurrent cytotoxic systemic therapy Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics At least 2 weeks since prior radiotherapy to gastrointestinal tract No concurrent radiotherapy to gastrointestinal tract Surgery: Not specified Other: At least 2 weeks since prior 5-HT3 receptor antagonists (i.e., dolasetron, granisetron, or ondansetron) No other concurrent 5-HT3 receptor antagonists Other concurrent antiemetics allowed