All subjects will be treated with study drug or placebo for 12 weeks. Subjects will be seen in the clinic for the following visits: Screening, Baseline (Day 1), Day 2, Day 4, Day 7 (Week 1), Week 2, Week 4, Week 6, Week 8,and Week 12 while on study drug. An additional safety visit at Week 14 (two weeks after study drug discontinuation) will be required of study participants.