This study will evaluate the potential drug-drug interaction of Dimebon with the FDA-recommended CYP2C9 substrate warfarin in healthy subjects. Conformance with the guidance includes general study design using a randomized, open label, single-dose warfarin, steady-state Dimebon, 2-sequence, 2-treatment, 2-period crossover design with a minimum 7-day washout period between treatments.

Inclusion Criteria:

• Healthy male and/or female (non-childbearing potential) subjects between the ages of 18 and 55 years, inclusive (Healthy is defined as no clinically relevant abnormalities identified by a detailed medical history, full physical examination, including blood pressure and pulse rate measurement, 12 lead ECG and clinical laboratory tests).
• Prothrombin time (PT)/INR, and partial thromboplastin time (PTT).
• Plasma Protein C and Protein S activity (functional) within the normal reference range.

Exclusion Criteria:

• A known sensitivity or previous intolerance to Dimebon or warfarin.
• Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic, or allergic (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at time of dosing) disease or clinical findings at Screening.
• Subjects receiving warfarin for treatment of active thromboembolic events (ie, pulmonary embolism, deep vein thrombosis), as well as subjects anticoagulated with prosthetic heart valves.