16. Females who have begun menstruation and are thus of child-bearing potential may be enrolled but must be documented not to be pregnant by serum pregnancy testing at screening. They also must be practicing an effective means of birth control (abstinence, oral contraceptives, hormonal implants in place at least 1 month prior to enrollment, or a double-barrier method), which must be documented, and the subject and caregiver must be counseled in writing of the importance of not becoming pregnant during the trial. A urine pregnancy test will be done at the Week 4 clinic visit and must be negative prior to dispensing any medication; a serum pregnancy test will be repeated at the Week 10 (or Early Termination) clinic visit.