Citalopram
| Evidence Level: L5 | Predicted Indications: 5 |
Table of Contents
Citalopram: From SSRI Antidepressant to Obsessive-Compulsive Disorder
One-Sentence Summary
Citalopram is a selective serotonin reuptake inhibitor (SSRI) marketed in the US as generic tablets. The TxGNN model predicts it may be effective for Obsessive-Compulsive Disorder (OCD), supported by 30 clinical trials and 16 publications. Most of these trials test escitalopram, a closely related molecule, rather than citalopram itself, so the evidence is strong at the class level but thin for citalopram specifically.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not listed in the provided records (indication text is empty); citalopram is an SSRI antidepressant |
| Predicted New Indication | Obsessive-compulsive disorder |
| TxGNN Prediction Score | 99.74% |
| Evidence Level | L2 (as assigned in the Evidence Pack; based mainly on class-level and escitalopram trials, not citalopram-specific RCTs) |
| US Market Status | ✓ Marketed |
| Number of NDAs | 20 authorizations (mostly ANDA generics) |
| Recommended Decision | Proceed with Guardrails |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Based on known information, citalopram belongs to the SSRI class. Serotonin reuptake inhibition is the best-established pharmacological mechanism in OCD, and SSRIs are a first-line drug class for it. This mechanism is inferred from drug class, not from a source record.
The clinical evidence follows the same pattern. Trials of escitalopram, the S-enantiomer of citalopram, are the largest body of OCD data in this pack. They include a randomized, double-blind, multi-center comparison of 20 mg versus 40 mg (NCT00723060) and a Phase 3 open-label high-dose study (NCT00305500). Two older publications look at citalopram directly in OCD, including treatment-resistant cases (PMIDs 10471169, 10572334). Together these support the class effect and a near-molecule effect, but not a definitive citalopram-specific efficacy claim.
Some OCD patients need higher SSRI doses than those used for depression. This makes the dose-related safety limits of citalopram, described in the Safety Considerations section, central to any repurposing plan.
Clinical Trial Evidence
The Evidence Pack lists 30 trials for this prediction. The 10 most relevant are shown below.
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT00723060 | Phase 4 | Completed | 176 | Randomized, double-blind, multi-center comparison of escitalopram 20 mg vs 40 mg in OCD, with Y-BOCS efficacy and safety endpoints |
| NCT00305500 | Phase 3 | Completed | 100 | Open-label study of high-dose escitalopram (up to 50 mg/day) in adult OCD outpatients over 18 weeks |
| NCT00116532 | Phase 4 | Completed | 30 | Escitalopram efficacy and optimal dose in OCD |
| NCT00215137 | Phase 2 | Completed | 14 | Pilot study of escitalopram safety and effectiveness for OCD symptoms |
| NCT00074815 | Phase 3 | Completed | 124 | Cognitive behavioral therapy added to serotonin reuptake inhibitor treatment in children with OCD who were partial responders |
| NCT00680602 | Phase 4 | Completed | 158 | Randomized open trial of group CBT vs fluoxetine in OCD, including patients with comorbid psychiatric disorders |
| NCT02022709 | Phase 4 | Completed | 78 | Exposure and response prevention, SSRIs, and their combination in OCD, with predictors of response in a Chinese population |
| NCT00564564 | Phase 4 | Completed | 21 | Open comparison of quetiapine vs clomipramine augmentation in SSRI-refractory OCD |
| NCT00456937 | Phase 4 | Completed | 15 | Open-label escitalopram up to 20 mg/day in patients with schizophrenia and comorbid OCD |
| NCT00086645 | Phase 2 | Completed | 149 | Citalopram vs placebo in children with autism spectrum disorders and high levels of repetitive behavior (a related symptom domain, not OCD) |
Literature Evidence
The Evidence Pack lists 16 publications. The 10 most relevant are shown below.
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 28477500 | 2017 | Meta-analysis | J Affect Disord | Compares antidepressant and placebo responses in OCD with other anxiety disorders; OCD shows a reduced placebo response |
| 35121274 | 2022 | Meta-analysis | J Psychiatr Res | Network meta-analysis of drug, psychological, and combined treatment in children and adolescents with OCD |
| 32982805 | 2020 | Meta-review | Front Psychiatry | Reviews efficacy, tolerability, and suicidality of antidepressants across pediatric disorders, including OCD |
| 38703743 | 2024 | Review | Compr Psychiatry | Examines long-term safety and tolerability of off-label high-dose serotonin reuptake inhibitors in OCD |
| 10572334 | 1999 | Open-label trial | Eur Psychiatry | Randomized, open-label, 90-day trial in 16 treatment-resistant OCD patients comparing citalopram alone vs citalopram plus clomipramine |
| 10471169 | 1999 | Clinical report / Review | Int Clin Psychopharmacol | Reviews the use of citalopram in OCD and the link between serotonin reuptake inhibitors and OCD neurobiology |
| 32242450 | 2020 | Systematic review | Nord J Psychiatry | Meta-analysis of fluoxetine efficacy, acceptability, and tolerability in pediatric OCD (a class-level reference) |
| 34313207 | 2022 | Clinical study | CNS Spectr | Tests whether the BDNF Val66Met polymorphism affects response to escitalopram or paroxetine in OCD |
| 30973183 | 2019 | Clinical study | Psychiatry Clin Neurosci | 1H-MRS study of brain neurochemistry in 28 unmedicated OCD patients and changes after 12 weeks of escitalopram |
| 22305974 | 2012 | Review | BMJ Clin Evid | Overview of OCD: about 1% of adult men and 1.5% of adult women are affected, and about 2.7% of children and adolescents |
US Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| ANDA078216 | Citalopram (Cardinal Health 107, LLC) | Tablet, film coated | Not listed in record |
| ANDA077031 | Citalopram (A-S Medication Solutions) | Tablet, film coated | Not listed in record |
| ANDA078216 | Citalopram (REMEDYREPACK INC.) | Tablet, film coated | Not listed in record |
| ANDA202389 | Escitalopram (NuCare Pharmaceuticals, Inc.) | Tablet, film coated | Not listed in record |
| Not listed | Citalopram (Hahnemann Laboratories, INC.) | Pellet | Not listed in record |
The pack records 20 authorizations in total; these 5 are shown. Dosage forms across the records include film-coated tablets, tablets, pellets, and solutions.
Safety Considerations
Package insert warnings, contraindications, and drug-interaction data were not available in the Evidence Pack. Please refer to the package insert for full safety information.
The following guardrails come from the Evidence Pack’s repurposing assessment:
- QT prolongation: Citalopram carries a dose-dependent QT-prolongation limit. The higher-than-depression doses often used in OCD (see PMID 38703743) call for ECG monitoring.
- CYP2C19 metabolism: Genotype and plasma-level information may help with dose personalization. NCT05210140 (n=148) studies this for escitalopram, which shares the CYP2C19 pathway.
Conclusion and Next Steps
Decision: Proceed with Guardrails
Rationale: The class-level rationale is strong: SSRIs are a first-line OCD drug class, and many trials of the near-molecule escitalopram are in this pack. Citalopram-specific OCD evidence is limited to two older publications, and the dose-dependent QT limit makes the higher doses used in OCD a real safety concern.
The other four TxGNN predictions for citalopram are histrionic, schizoid, schizotypal, and paranoid personality disorders. All are rated Hold. They share an identical score of 99.68%, which suggests a class-level graph artifact rather than independent signals, and they have no supporting clinical trials.
To proceed, the following is needed:
- FDA package insert warnings and contraindications (a blocking gap for safety screening)
- Detailed mechanism of action data from DrugBank
- Evidence from citalopram-specific OCD trials, or a justification for extrapolating from escitalopram
- A dosing and monitoring plan for higher-dose use, covering ECG/QT surveillance and CYP2C19 considerations
- The approved indication text for the US licenses, to confirm the original indication
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.