A study to obtain safety and tolerability data

Inclusion Criteria:

• Patient must have primary diagnosis of Major Depressive Disorder (MDD).
• Discontinued a selective serotonin reuptake inhibitor (SSRI)or serotonin-norepinephrine reuptake inhibitor (SNRI) regimen due to intolerability.
• Minimum time frame between last dose of previous antidepressant and initiation of study drug is one week.
• Maximum time frame between last dose of prior antidepressant and initiation of study drug is 2 months.

Exclusion Criteria:

• Patient has previously been treated with the study drug.
• Is experiencing an adverse event attributed to previous SSRI/SNRI use that has not been resolved at least one week prior to Baseline Visit.
• Has a history of seizure disorder.
• Has met criteria for substance abuse or dependence within 6 months prior to Baseline Visit.
• Currently using an antidepressant.
• Currently pregnant.