Tipifarnib in Treating Young Patients With Recurrent or Progressive High-Grade Glioma, Medulloblastoma, Primitive Neuroectodermal Tumor, or Brain Stem Glioma

Inclusion Criteria: * Histologically confirmed brain tumor, including the following: * Anaplastic astrocytoma * Glioblastoma multiforme * Gliosarcoma * Anaplastic oligodendroglioma * Medulloblastoma/primitive neuroectodermal tumor (PNET) * Diffuse intrinsic brain stem glioma\* * Progressive or relapsed disease after prior conventional therapy * Radiographic evidence of measurable disease * Performance status - Karnofsky 60-100% (over 16 years of age) * Performance status - Lansky 60-100% (16 years of age and under) * Performance status - ECOG 0-2 * At least 8 weeks * Absolute neutrophil count at least 1,000/mm\^3 * Platelet count at least 100,000/mm\^3 (transfusion independent) * Hemoglobin at least 8.0 g/dL (red blood cell transfusions allowed) * Bilirubin no greater than 1.5 times upper limit of normal (ULN) * SGPT and SGOT less than 2.5 times ULN * Creatinine clearance OR radioisotope glomerular filtration rate at least 70 mL/min * Maximum creatinine based on age as follows: * 0.8 mg/dL (5 years and under) * 1.0 mg/dL (6 to 10 years) * 1.2 mg/dL (11 to 15 years) * 1.5 mg/dL (over 15 years) * Shortening fraction at least 27% by echocardiogram * Ejection fraction at least 50% by MUGA * No dyspnea at rest * No exercise intolerance * Pulse oximetry greater than 94%\* * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Seizure disorder is allowed provided it is well-controlled on non-enzyme-inducing anticonvulsants * No active graft-versus-host disease * No uncontrolled infection * No allergy to azoles (e.g., ketoconazole, itraconazole, or fluconazole) * Recovered from prior immunotherapy * At least 7 days since prior antineoplastic biologic agents * At least 1 month since prior autologous stem cell transplantation (SCT) * At least 6 months since prior allogeneic SCT * More than 1 week since prior growth factors * No concurrent immunomodulating agents * More than 2 weeks since prior myelosuppressive chemotherapy (4-6 weeks for nitrosoureas or temozolomide) and recovered * No concurrent anticancer chemotherapy * Concurrent dexamethasone allowed provided patient is on a stable or decreasing dose for at least 1 week prior to study entry * Concurrent corticosteroids allowed only for treatment of increased intracranial pressure * Recovered from prior radiotherapy * At least 2 weeks since prior local palliative radiotherapy (small port) * At least 3 months since prior craniospinal radiotherapy * At least 6 weeks since other prior substantial bone marrow radiotherapy * No concurrent palliative radiotherapy * No prior initiation of therapy on another phase II study * No concurrent participation in another therapeutic COG study * No concurrent enzyme-inducing anticonvulsants * No other concurrent anticancer or experimental drugs * No concurrent foods or medications that interfere with CYP3A4, including any of the following: * Carbamazepine * Phenytoin * Phenobarbital * Grapefruit juice * Erythromycin * Azithromycin * Clarithromycin * Rifampin and its analogues * Fluconazole * Ketoconazole * Itraconazole * Cimetidine * Cannabinoids (i.e., marijuana or dronabinol) * Omeprazole * Hypericum perforatum (St. John's wort) * Ethosuximide * Glucocorticoids * Griseofulvin * Nafcillin * Nelfinavir * Norfloxacin * Norfluoxetine * Nevirapine * Oxcarbazepine * Phenylbutazone * Primidone * Progesterone (all progestins) * Rifabutin * Rofecoxib * Sulfadimidine * Sulfinpyrazone * Troglitazone * Rifapentine * Modafinil * Amiodarone * Anastrozole * Clotrimazole * Cyclosporine * Danazol * Delavirdine * Diethyldithiocarbamate * Diltiazem * Dirithromycin * Disulfiram * Entacapone (high dose) * Ethinyl estradiol * Fluoxetine * Fluvoxamine * Gestodene * Indinavir * Isoniazid * Metronidazole * Mibefradil * Miconazole * Nefazodone * Oxiconazole * Paroxetine * Propoxyphene * Roxithromycin * Quinidine * Quinine * Quinupristin and dalfopristin * Ranitidine * Ritonavir * Saquinavir * Sertindole * Sertraline * Troleandomycin * Valproic acid * Verapamil * Voriconazole * Zafirlukast * Zileuton