DISEASE CHARACTERISTICS:

Part I:

• Histologically proven advanced solid tumors that are refractory or for which no curative therapy exists
• No CNS metastases, peritumoral edema, or symptomatic brain metastases (part I)
• Measurable or evaluable disease

Part II:

• Histologically proven recurrent gliomas or brain metastases for which no curative therapy exists
• Receiving anticonvulsants
• Measurable or evaluable disease

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2

Life expectancy:

• At least 3 months

Hematopoietic:

• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 9 g/dL

Hepatic:

• Bilirubin less than 1.5 mg/dL
• AST or ALT less than 3 times upper limit of normal (ULN) (less than 5 times ULN if liver metastases)

Renal:

• Creatinine less than 2 mg/dL

Cardiovascular:

• No unstable angina
• No myocardial infarction within past 6 months
• No maintenance therapy for life-threatening arrhythmias

Other:

• Not pregnant or nursing
• Fertile patients must use effective contraception
• HIV negative
• No active infection or other serious concurrent illness
• Triglycerides no greater than 300 mg/dL
• Cholesterol no greater than 350 mg/dL
• No known hypersensitivity to macrolide antibiotics (e.g., clarithromycin, erythromycin, or azithromycin)

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• At least 3 weeks since prior chemotherapy (6 weeks since nitrosoureas and mitomycin)
• No other concurrent chemotherapy

Endocrine therapy:

• Concurrent corticosteroids used to reduce edema in patients with primary or metastatic CNS tumors allowed
• No concurrent hormonal therapy

Radiotherapy:

• At least 3 weeks since prior radiotherapy
• No concurrent radiotherapy

Surgery:

• Not specified

Other:

• At least 1 month since prior investigational agents
• At least 3 weeks since prior immunosuppressive therapy
• No concurrent anticonvulsant therapy (part I)
• No concurrent immunosuppressive therapy (e.g., terfenadine, cisapride, astemizole, pimozide)
• No known agents that inhibit or induce cytochrome p450