PATIENT CHARACTERISTICS: Age: 18 and over Performance Status: ECOG 0-1 Life Expectancy: Not specified Hematopoietic: Not specified Hepatic: No grade 3 or greater hepatic dysfunction Renal: No hypercalcemia Cardiovascular: No uncontrolled hypotension Other: Not pregnant or nursing Effective contraceptive method must be used by fertile patients No psychosis No severe concurrent illness other than neoplasia No epileptic seizures during the previous year, migraines, gastrointestinal obstructions, or other causes of vomiting No prior or concurrent amifostine contraindications No prior known contraindications or sensitivity to dexamethasone, granisetron, ondansetron, prochlorperazine, diphenhydramine, cimetidine, or magnesium