Inclusion Criteria:  Are fluent in speaking and reading the predominantly used or recognized language of the study site. Are able to swallow pills. If of childbearing potential, must have a negative pregnancy test at study entry and prior to each Experimental Session, and must agree to use adequate birth control through 7 days after the last Experimental Session.  Exclusion Criteria:  Are not able to give adequate informed consent. Have uncontrolled hypertension. Have a marked baseline prolongation of QT/QTc interval (e.g., repeated demonstration of a QTc interval >450 milliseconds [ms] corrected by Bazett's formula). Have a history of additional risk factors for Torsade de pointes (e.g., heart failure, hypokalemia, family history of Long QT Syndrome). Have evidence or history of significant medical disorders. Have symptomatic liver disease. Have history of hyponatremia or hyperthermia. Weigh less than 48 kilograms (kg). Are pregnant or nursing, or are of childbearing potential and are not practicing an effective means of birth control. Are abusing illegal drugs.