Riluzole in Treating Patients With Stage III or Stage IV Melanoma That Cannot Be Removed by Surgery

DISEASE CHARACTERISTICS: * Histologically confirmed malignant melanoma * Unresectable stage III or stage IV disease * Measurable disease according to RECIST criteria, defined as ≥ 1 unidimensionally measurable lesion \> 20 mm by conventional techniques or \> 10 mm by spiral CT scan * No known brain metastases unless treated and stable for ≥ 2 weeks by MRI evaluation PATIENT CHARACTERISTICS: * ECOG performance status 0-2 * ANC ≥ 1,000/μL * Platelet count ≥ 50,000/μL * Total bilirubin ≤ 2 times upper limit of normal (ULN) * AST/ALT ≤ 3 times ULN * INR ≤ 1.5 times ULN * Not pregnant * Negative pregnancy test * Fertile patients must use effective contraception during and for 2 weeks after completion of study treatment * No second primary malignancy, except carcinoma in situ of the cervix, adequately treated nonmelanoma carcinoma of the skin, or other malignancy treated ≥ 5 years ago with no evidence of recurrence * No concurrent serious systemic disorders (including active infections) that, in the opinion of the investigator, would compromise the safety of the patient or compromise the patient's ability to complete the study * No history of allergic reactions attributed to riluzole * No known history of hepatitis B or C PRIOR CONCURRENT THERAPY: * No more than 1 prior therapeutic chemotherapy regimen for advanced melanoma * Prior treatment with riluzole on clinical trial CINJ-090603 allowed * No other concurrent investigational or commercial agents or therapies for the treatment of the malignancy