Medication Therapy Management Empowerment Act of 2013 - Amends part D (Voluntary Prescription Drug Benefit Program) of title XVIII (Medicare) of the Social Security Act to provide access to services under medication therapy management programs for Medicare part D (Voluntary Prescription Drug Program) eligible individuals with a single chronic disease. Allows the application of this Act only if the Chief Actuary for the Centers for Medicare & Medicaid Services determines that such application with regard to a particular single chronic disease is not projected to increase overall costs to the Medicare program over the following five year period.