Second, urine and blood samples will be needed for routine tests two times during this study (before any study related tests are done, and at the end of the study). Two teaspoons of blood will be drawn each time. The urine sample will be analyzed in order to assess kidney function and to screen for the presence of drugs (such as cocaine, marijuana, heroin, etc.). A positive drug screen would result in the inability of the child to participate in this study. Drug screen results will be kept confidential. In addition, an electrocardiogram will be performed to determine heartbeat.