Naturalistic study of the early psychiatric use of citalopram in the United States.

We obtained information on the efficacy and safety of citalopram in settings that resemble actual clinical practice. A total of 1,783 patients participated in this open, uncontrolled, naturalistic Phase IV evaluation of citalopram at 447 U.S. investigative sites. Participants were selected by guidelines in the citalopram package insert using minimal exclusion criteria. Citalopram dosing began at 20 mg/day and could be titrated to 60 mg/day. Outcomes included the Clinical Global Impressions-Improvement scale (CGI-I) and a Patient Global Evaluation. Separate analyses were performed on patients with a primary diagnosis of major depressive disorder (MDD) (76%) who reported intolerance or nonresponse to previous selective serotonin reuptake inhibitors (SSRIs). Patients included tended to have treatment-resistant or intolerant, chronic or recurrent, comorbid depression with a mean duration of illness of 10 years. At study completion, more than 68% of treatment completers were classified as responders (CGI-I score of 1 or 2). Endpoint analyses showed response rates of 54% in all patients, 56% in patients with MDD, 49% in SSRI nonresponsive patients, and 53% in patients with a history of SSRI intolerance. Nausea (9.8%) and headache (7.3%) were the most often reported adverse events. Patients with a history of SSRI intolerance had a discontinuation rate of 21.8%, whereas those without such a history had a discontinuation rate of 13.3%. Citalopram administered at an average dose of 23.6 mg/day was associated with favorable outcomes and was generally well tolerated.