Study of Rifampicin in Multiple System Atrophy

Inclusion Criteria: * Participants aged 30-80 years old with a diagnosis of Possible or Probable MSA of the parkinsonian subtype (MSA-P) or cerebellar subtype (MSA-C) according to The Gilman Criteria (2008). * Participants who are less than 4 years from the time of documented MSA diagnosis. * Participants with an anticipated survival of at least 3 years in the opinion of the investigator. * Participants who are willing and able to give informed consent. * "Normal" cognition as assessed by Mini-Mental State Examination (MMSE). We will require a value \>24. * Patients should be able to swallow capsules whole. Exclusion Criteria: * Pregnant or lactating females. * Unified Multiple System Atrophy Rating Scale (UMSARS) score \>17 on modified UMSARS I (question 11 eliminated). * Participants with a clinically significant or unstable medical or surgical condition that, in the opinion of the investigator, might preclude safe completion of the study or might affect the results of the study. These include conditions causing significant Central Nervous System (CNS) or autonomic dysfunction, including congestive heart failure, recent (\<6 months) myocardial infarct, thrombocytopenia (\<50 x10(9)/L), immunosuppressed state, severe uncontrolled hypertension, severe cardiopulmonary disease, severe anemia (\<8g/dl), severe liver or kidney disease (creatinine \>2.3 mg/dl) uncontrolled diabetes mellitus (HbA1c \>10g%), alcoholism, malignant neoplasms, amyloidosis, uncontrolled hypothyroidism, unstable peripheral neuropathies, concurrent infections, orthopedic problems that compromise mobility and activity of daily living, severe cerebrovascular accidents (such as hemiplegia, aphasia and non-dominant parietal lobe syndrome), and neurotoxins or neuroactive drug exposure, parkinsonism due to drugs (including neuroleptics, a-methyldopa, reserpine, metoclopramide). * Participants who have taken any investigational products within 60 days prior to baseline. * Women of child-bearing potential who do not practice an acceptable method of birth control. Acceptable methods of birth control in this study are: surgical sterilization, intrauterine devices, partner's vasectomy, a double-protection method (condom or diaphragm with spermicide), hormonal contraceptive drug (i.e., oral contraceptive, contraceptive patch, long-acting injectable contraceptive) with a required second mode of contraception. * Participants taking Tetrabenazine, Rasagiline or Selegiline. The participant will qualify for the Rifampicin study after they have stopped these drugs for 3 months * Participants known to have porphyria. * Participants with abnormal liver function tests defined as 1.5 times the upper limit of normal. * Concomitant therapy with anticholinergic, alpha and beta adrenergic antagonists, or other medications that affect autonomic function will be stopped prior to autonomic evaluation. * The regular use of neuroleptics within the six months prior to the initial evaluation. Occasional use of a neuroleptic as an anti-emetic in the past is allowed, providing not more than three doses were taken within the previous 12 months. * Since Rifampicin has significant drug-drug interactions, particular attention has been devoted to the use of concomitant medications. Considering the target population, we will exclude participants taking antifungal medication (itraconazole), antiarrhythmics like amiodarone, digitalis and lorcainide, female hormones and quetiapine (Seroquel). Use of methylphenidate, cinnarizine, reserpine, amphetamine, atypical antipsychotics such as risperidone, olanzapine, and quetiapine or a Monoamine oxidase A (MAO-A) inhibitor within one month prior to the baseline visit are also exclusionary. * Diseases with features of Parkinson's Disease; e.g., progressive supranuclear palsy, essential tremor, inherited cerebellar degeneration, or postencephalitic parkinsonism. * Dementia (DSM-IV criteria - Amer. Psych. Association, 1994). The score on the MMSE must be \>24.