Ketamine for Major Depressive Disorder

Inclusion Criteria:

* Present a current depressive episode of at least 8 weeks
* Have a body mass index (BMI) of 18-35 kg/m2 (inclusive) at screening
* Agree to use adequate methods of contraception during the study (and for X days after discharge)

Exclusion Criteria:

* A history of alcohol consumption exceeding 14 drinks/week within the 5 years before study entry.
* Use of prescription or non-prescription drugs, vitamins, or dietary supplements within 14 days prior to the first dose of study medication except ongoing stable dose of antidepressant.
* Treatment with any investigational drug, use of any known CYP3A4 enzyme-inducing/inhibiting agents (e.g., barbiturates, phenothiazines, cimetidine, St. John's Wort) or herbal supplements within 7 days prior to the first dose of study medication
* A history of drug abuse or dependence within 180 days of screening
* A febrile illness within 5 days prior to the first dose of study medication.
* A known hypersensitivity to ketamine
* A history of use ketamine for Major Depressive Disorder and did not respond to ketamine
* Recent use of ketamine in any formulation for any indication (within 4 weeks prior to screening)