Inclusion Criteria:

   - Histologically confirmed diagnosis of a primary malignant brain tumor or, if
   metastatic, documentation and histology (if available) of primary source of cancer.

   - Patient must have 1 or more qualifying steroid-associated side effect(s) at Baseline.

   - Patient has required administration of dexamethasone to control symptoms of
   peritumoral edema for at least 30 days.

   - Stable dexamethasone dose of 4-24 mg/day for at least 14 days prior to Baseline.

   - Need for administration of dexamethasone to treat peritumoral brain edema (referenced
   above) has been documented by MRI or comparable diagnostic technology within 21 days
   of Baseline.

   - Karnofsky score of > 50 at Screening and Baseline.

   - Capable of self-administration of subcutaneous injections twice daily for 12 weeks, or
   availability of assistance from caregiver.

   - Ability to provide written informed consent or, if unable to provide, have a legal
   guardian or representative provide written informed consent.

   - For women of childbearing potential: a negative serum pregnancy test at Screening.

   - Must be 18 years of age or older

Exclusion Criteria:

   - Ongoing or anticipated need for surgery, radiosurgery or radiation therapy or the
   introduction of new chemotherapeutic regime within the first 5 weeks of study
   enrollment. Treatment with pre-study chemotherapy may continue.

   - Concurrent enrollment in any other investigational drug or device study, or plan to
   enroll in such a study during the first 5 weeks of treatment.

   - Systemic steroid use for any indication other than peritumoral brain edema.

   - Use or intended use of dexamethasone as an anti-emetic during Screening or Study

   - Non-compliance with dexamethasone or anticonvulsant therapy.

   - Clinical signs and symptoms of cerebral herniation.

   - Serious concomitant cardiovascular, pulmonary, renal, gastrointestinal or endocrine
   metabolic disease which could put the patient at unusual risk for study participation.

   - Confounding previous or concurrent neurological disorders that would interfere with
   adequate clinical evaluation.

   - Clinically significant head injury or chronic seizure disorder, if the condition
   results in functional impairment or is likely to interfere with evaluations.
   (Maintenance anticonvulsant therapy is allowed.)

   - Central nervous system infection.

   - Pregnancy, breastfeeding and/or refusal to practice birth control while in study, for
   women of childbearing potential.

   - Any conditions that are considered contraindications for patients to receive niacin,
   e.g. liver disease (with LFTs > 3 times the upper limit of the norm),active peptic
   ulcer, arterial hemorrhage, asthma and known hypersensitivity to niacin.