DISEASE CHARACTERISTICS:

• Histologically proven malignant glioma of one of the following types:

  • Anaplastic astrocytoma
  • Anaplastic oligodendroglioma
  • Glioblastoma multiforme
• Progressive or recurrent disease after radiotherapy with or without chemotherapy
• Measurable disease by serial MR or CT

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 60-100%

Life expectancy:

• Greater than 2 months

Hematopoietic:

• Absolute neutrophil count at least 1500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin no greater than 1.5 mg/dL
• SGPT/SGOT no greater than 4 times upper limit of normal

Renal:

• Creatinine no greater than 1.7 mg/dL

Other:

• No serious concurrent infection
• No other illness that would preclude study
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No prior malignancy within the past 5 years except curatively treated basal cell skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No concurrent filgrastim (G-CSF) during the first course

Chemotherapy:

• See Disease Characteristics
• No more than 1 prior chemotherapy regimen
• At least 3 weeks since prior chemotherapy (at least 6 weeks since prior nitrosoureas)
• No more than 2 prior courses of carmustine or lomustine and no greater than 460 mg/m2 or 220 mg/m2, respectively
• No prior procarbazine

Endocrine therapy:

• Not specified

Radiotherapy:

• See Disease Characteristics
• At least 3 months since prior radiotherapy

Surgery:

• Prior surgery allowed

Other:

• Recovered from toxicity of prior therapy
• At least 10 days since prior anticonvulsants for patients in Arm II
• No concurrent investigational agents
• No concurrent ethanol, ephedrine, isoproterenol, epinephrine, tricyclic antidepressants, paragyliline, narcotic analgesics, antihistamines, phenothiazines, hypotensives, or barbiturates
• At least 14 days since prior antidepressants (e.g., SSRI and/or MAO inhibitor)
• Must avoid foods high in tyramine (i.e., dark beer, wine, yogurt, cheese, bananas)