Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed solid tumor

- Has ≥ 2 brain metastases as demonstrated by baseline MRI

- Patients with only 1 metastasis are eligible provided the metastasis is too
large for radiosurgery and not amenable to surgical resection

- Not being considered for surgical resection

- Eligible to undergo whole-brain radiotherapy (WBRT)

PATIENT CHARACTERISTICS:

- ECOG performance status 0-2

- ANC ≥ 1,000/μL

- Platelet count ≥ 50,000/μL

- Total bilirubin ≤ 1.5 times upper limit of normal (ULN)

- AST/ALT ≤ 1.5 times ULN

- INR ≤ 1.5 times ULN

- Sodium normal

- Thyroid-stimulating hormone normal

- Negative pregnancy test

- Fertile patients must use effective contraception before, during, and for ≥ 6 months
after completion of study treatment

- No headaches, disequilibrium, vertigo, or dizziness

- No known history of hepatitis B or C

- No concurrent serious systemic disorder (including active infection) that would
compromise the safety of the patient or compromise the patient's ability to complete
the study, at the discretion of the investigator

- No history of allergic reactions attributed to riluzole

PRIOR CONCURRENT THERAPY:

- No prior WBRT

- At least 2 weeks since prior systemic chemotherapy

- No systemic chemotherapy during and for ≥ 3 weeks after completion of WBRT

- Radiosurgical boosts to ≤ 3 metastases allowed, based on the discretion of the
treating radiation oncologist