This is a research study comparing the safety and efficacy of two active study medications

Inclusion Criteria:

• Male or female subjects 18-60 years of age
• Female subjects of childbearing potential must be using a medically accepted means of contraception
• Each subject must have a level of understanding sufficient to perform all tests and examinations required by the protocol
• Subjects must be considered reliable

Exclusion Criteria:

• Treatment with a drug within the last 30 days that has not received regulatory approval at the time of study entry
• Female subjects who are either pregnant or nursing
• Uncorrected hypothyroidism or hyperthyroidism
• Narrow-angle glaucoma