PARENTERAL clomipramine showed no clear early advantage over oral therapy for depression, while evidence in OCD remained limited.
Parenteral Clomipramine in Depression and OCD
A new systematic review and meta-analysis suggests parenteral clomipramine may not offer a meaningful short-term benefit over oral clomipramine for severe depression, while the evidence base in OCD remains too weak and inconsistent to support firm conclusions. The review examined whether parenteral clomipramine reduced depressive or OCD symptoms within 2 weeks better than oral treatment or other comparators.
Across 4,973 unique publications screened, 14 randomized controlled trials contributed data to the review question. However, the strongest conclusions rested on trials without a high risk of bias, and the authors repeatedly emphasized the limited certainty of the available evidence.
Depression Findings Show No Clear Short-Term Edge
For depression, parenteral clomipramine did not clearly outperform oral administration within 2 weeks. Five randomized trials involving 70 patients informed this conclusion, with a meta-analysis of 3 trials showing a mean difference in change on the Hamilton Depression Rating Scale of -1.27. The 95% confidence interval ranged from -3.09 to 0.54, meaning a clinically relevant effect could not be ruled out, but superiority was not demonstrated. Certainty of evidence was rated low.
That nuance is important for clinicians. The signal was not strong enough to establish parenteral clomipramine as a preferable route, yet the data were also too limited to fully exclude benefit in selected severe cases.
OCD Evidence Remains Too Sparse
For OCD, only 2 randomized trials involving 47 patients were available, and heterogeneity prevented meta-analysis. As a result, no clear conclusion could be drawn. The certainty of evidence was judged very low, leaving a major evidence gap for clinicians managing severe OCD in situations where parenteral treatment is being considered.
The review also found little help from comparator studies beyond oral clomipramine. In depression, the single randomized comparison with another treatment did not permit conclusions, and no randomized comparator trials were available for OCD.
Taken together, the findings suggest parenteral clomipramine is not currently supported as a favorable alternative to oral administration on the basis of existing evidence. Just as notably, the review highlights the absence of randomized trials against clinically relevant comparators such as electroconvulsive therapy and ketamine, underscoring how much uncertainty still surrounds its place in practice.
Reference
Ioannou M et al. Parenteral Clomipramine for Depression or Obsessive-Compulsive Disorder: A Systematic Review and Meta-Analysis. Acta Neuropsychiatr. 2026;10.1017/neu.2026.10074.
Featured Image: mnirat on Adobe Stock.
