DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed incurable primary malignant brain tumor that has progressed during or is recurrent after prior initial therapy, including radiotherapy

  • Failed prior standard therapy
• Measurable disease by MRI or CT scan
• No brain stem tumors

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 60-100%

Life expectancy:

• At least 2 months

Hematopoietic:

• Hematological function normal
• WBC at least 2000/mm^3
• Platelet count at least 50,000/mm^3

Hepatic:

• No liver failure
• No evidence of hepatic insufficiency
• Bilirubin no greater than 2.5 mg/dL
• SGOT/SGPT no greater than 5 times upper limit of normal

Renal:

• No evidence of renal insufficiency
• Creatinine no greater than 2.5 mg/dL
• No history of renal conditions that contraindicate high dosages of sodium

Cardiovascular:

• No uncontrolled hypertension
• No history of congestive heart failure
• No chronic heart failure
• No other cardiovascular conditions that contraindicate high dosages of sodium

Pulmonary:

• No serious lung disease, such as severe chronic obstructive pulmonary disease

Other:

• Not pregnant or nursing
• Fertile patients must use effective contraception during and for 4 weeks after study participation
• No medical or psychiatric illness that would preclude study treatment
• No active infection

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• At least 4 weeks since prior immunotherapy
• No concurrent immunomodulating agents

Chemotherapy:

• At least 4 weeks since prior chemotherapy, except in patients with disease progression during initial therapy
• At least 6 weeks since prior nitrosoureas, except in patients with disease progression during initial therapy
• No concurrent antineoplastic agents

Endocrine therapy:

• Corticosteroids allowed

Radiotherapy:

• See Disease Characteristics
• At least 8 weeks since prior radiotherapy, except in patients with disease progression during initial therapy

Surgery:

• At least 4 weeks since prior surgery, except in patients with disease progression during initial therapy

Other:

• Recovered from prior therapy
• Cytodifferentiating agents allowed