Background: Selective serotonin reuptake inhibitors take several weeks to achieve their full antidepressant effects. Post-synaptic 5-HT2A receptor activation is thought to be involved in this delayed therapeutic effect. Pipamperone acts as a highly selective 5-HT2A/D4 antagonist when administered in low doses. The purpose of this study was to compare citalopram 40 mg once daily plus pipamperone 5 mg twice daily (PipCit) versus citalopram plus placebo twice daily for magnitude and onset of therapeutic effect.
Method: An 8-week, randomized, double-blind study in patients with major depressive disorder was carried out.
Results: The study population comprised 165 patients (citalopram and placebo, n=82; PipCit, n=83) with a mean baseline Montgomery-Asberg Depression Rating Scale (MADRS) score of 32.6 (s.d.=5.5). In the first 4 weeks, more citalopram and placebo than PipCit patients discontinued treatment (18% v. 4%, respectively, p=0.003). PipCit patients had significantly greater improvement in MADRS score at week 1 [observed cases (OC), p=0.021; last observation carried forward (LOCF), p=0.007] and week 4 (LOCF, p=0.025) but not at week 8 compared with citalopram and placebo patients. Significant differences in MADRS scores favoured PipCit in reduced sleep, reduced appetite, concentration difficulties and pessimistic thoughts. Mean Clinical Global Impression-Improvement scores were significantly improved after 1 week of PipCit compared with citalopram and placebo (OC and LOCF, p=0.002).
Conclusions: Although the MADRS score from baseline to 8 weeks did not differ between groups, PipCit provided superior antidepressant effects and fewer discontinuations compared with citalopram and placebo during the first 4 weeks of treatment, especially in the first week.
Trial registration: ClinicalTrials.gov NCT00672659.