The objective of this open-label, multicentre study was to evaluate the safety and efficacy of treatment with escitalopram (10 or 20 mg/day) for 6 weeks following a switch from intravenous citalopram treatment (20 or 40 mg/day) in patients presenting with a major depressive episode. A total of 173 patients were included, 147 (85%) of whom completed the study. The mean Montgomery-Asberg Depression Rating Scale (MADRS) total score at inclusion (last citalopram dose) was 31.6 +/- 9.9. The MADRS score decreased to 23.4 +/- 10.5 after 3 days of oral treatment with escitalopram and was 12.7 +/- 9.3 at the end of the study. The scores on the Clinical Global Impression (CGI) and Patient Global Evaluation scales also improved: at the end of the study, the response rates were 67% on the MADRS (defined as >= 50% decrease from MADRS baseline score) and 68% on the CGI-I (defined as CGI-I <= 2). More than half of the patients were in remission (MADRS score <= 12). Overall, the switch from intravenous citalopram to escitalopram was well tolerated. In all, 57 patients (33%) reported at least 1 adverse event, and 7 patients (4%) were withdrawn due to an adverse event. The most frequently reported adverse events were probably linked to residual depressive symptoms (anxiety: 9%; insomnia: 5%). In conclusion, escitalopram was well tolerated as a continuation treatment after switching from intravenous citalopram and reduced depressive symptoms in patients with a moderate to severe major depressive episode.