DISEASE CHARACTERISTICS:

• Histologically confirmed solid tumor that is refractory to standard therapy or for which no standard therapy exists
• Measurable or evaluable disease
• No CNS metastasis or primary CNS malignancy

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 60-100%

Life expectancy:

• Not specified

Hematopoietic:

• WBC greater than 3,500/mm^3
• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin no greater than 1.5 mg/dL
• SGOT and SGPT no greater than 2.5 times upper limit of normal

Renal:

• Creatinine no greater than 1.5 mg/dL OR
• Creatinine clearance greater than 60 mL/min

Cardiovascular:

• No history of coronary artery disease documented by prior myocardial infarction, angiography, or coronary-artery bypass grafting
• No cardiac arrhythmias or congestive heart failure within the past 6 months
• Stable atrial fibrillation on standard treatment allowed at discretion of investigator

Pulmonary:

• DLCO at least 60% of predicted

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 2 months after study
• No active serious or uncontrolled infection
• HIV negative
• No diabetes
• No other medical condition that would preclude study

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics

Biologic therapy:

• At least 4 weeks since prior immunotherapy and recovered

Chemotherapy:

• At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas and mitomycin) and recovered
• Prior fluorouracil allowed

Endocrine therapy:

• Not specified

Radiotherapy:

• No prior mediastinal radiotherapy
• At least 4 weeks since prior radiotherapy and recovered

Surgery:

• Not specified

Other:

• No concurrent anticonvulsant medications