PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: At least 12 weeks Hematopoietic: WBC at least 2,000/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 9 g/dL Hepatic: No hepatic failure No encephalopathy Bilirubin no greater than 2.5 times upper limit of normal (ULN) AST or ALT no greater than 2.5 times ULN Renal: No renal dysfunction requiring dialysis for greater than 72 hours Creatinine no greater than 2.0 mg/dL Cardiovascular: No history of sustained ventricular tachycardia (greater than 5 beats) No uncontrolled cardiac rhythm disturbances No recurrent chest pain with echocardiogram changes No angina No myocardial infarction No pericardial tamponade No moderate or severe coronary artery disease (New York Heart Association class 3 or 4) Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No significant neurological dysfunction including seizure or clinical signs of other significant neurological disease No gastrointestinal bleeding requiring surgery No concurrent infection requiring antimicrobial therapy No bowel ischemia or perforation