Summary
Clonidine Hydrochloride has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in ADHD would be drug repurposing rather than first-in-human development. This does not mean it is approved for ADHD. ClinicalTrials.gov lists 8 registered trials linking Clonidine Hydrochloride to ADHD: 2 are currently recruiting; 1 is active or not yet recruiting; 4 have completed; 1 is terminated, withdrawn, suspended or of unknown status. The most advanced is Phase 4 (NCT05916339). The largest enrolment is 5000 participants (NCT04278404). Registration activity spans 1999 to 2025. The literature layer holds 4 publications for this pair: 1 Cochrane review and 3 clinical trial publications. Publication years run from 2011 to 2026. Because at least one synthesis-level source exists (systematic review, meta-analysis or Cochrane review), this pair has been assessed beyond single studies, although the synthesis may concern a different indication.
The RepurpOS disease-intelligence file for Attention Deficit-Hyperactivity Disorder ranks 305 candidate therapeutics from Open Targets, ChEMBL, DGIdb and PubMed; only a minority carry direct clinical evidence, and this page covers one of those. Spontaneous remission context recorded for the condition: Spontaneous remission by adulthood: 30-70% symptom reduction (depending on definition); functionally impairing ADHD persists into adulthood in 50-65% of childhood cases; DSMIV criteria met in adulthood in ~50%.
Evidence table
| Evidence tier | A · Strong |
|---|---|
| Evidence score | 61.0 (trials 30.0, literature 11.0, tier 15, approved bonus 5.0) |
| Registered trials | 8 total: 2 recruiting, 1 active / not yet recruiting, 4 completed, 1 other |
| Linked publications | 4 (3 clinical trial publications, 1 Cochrane review) |
| Agent type | Drug (Small molecule) |
| Development stage (any indication) | Approved |
| Mechanism / class | agonist; agonist |
| Data sources | DGIdb |
| Linked via biomarker / target | ADRA2C |
How the evidence score is calculated
- Each registered trial scores by status (recruiting / active / enrolling 3, completed 2.5, not yet recruiting 2, unknown 1, terminated / withdrawn / suspended 0.5) plus a phase bonus (phase 3-4 +2, phase 2 +1, phase 1 +0.5). The trial component is capped at 30.
- Each literature item scores by design (Cochrane review 5, meta-analysis 4, systematic review 3, RCT 3, clinical trial publication 2, curated reference 1.5, other PubMed record 1). The literature component is capped at 30.
- The existing evidence tier adds 15 (A / Strong), 10 (B / Moderate), 5 (C / Preliminary) or 0 (D / Anecdotal).
- Agents approved for any indication (max clinical phase 4) add 5, because an approved agent has an established safety profile that lowers the barrier to repurposing trials.
- The score ranks what has been studied, not what works. It does not read effect sizes or directions of effect.
Registered clinical trials
| NCT ID | Title | Status | Phase | Enrolment |
|---|---|---|---|---|
| NCT07044609 | A Study to Assess the Effectiveness and Safety of Clonidine Extended-Release OnydaTM XR in Children With ADHD and ODD 2025 | not yet recruiting | Phase 4 | 162 |
| NCT05916339 | AWARE: Management of ADHD in Autism Spectrum Disorder 2023 | recruiting | Phase 4 | 500 |
| NCT00152750 | Study of Clonidine on Sleep Architecture in Children With Tourette's Syndrome (TS) and Comorbid ADHD 2006 | status unknown | Phase 4 | 32 |
| NCT00556959 | Study Evaluating the Safety and Efficacy of CLONICEL® to Treat Children and Adolescents With Attention Deficit Hyperactivity Disorder (ADHD) 2007 | completed | Phase 3 | 236 |
| NCT00641329 | CLONICEL (Clonidine Sustained Release) as Add-on to Stimulant Medication in 6 to 17 Yr-olds With ADHD 2008 | completed | Phase 3 | 198 |
| NCT00031395 | Clonidine in Attention Deficit Hyperactivity Disorder (ADHD) in Children 1999 | completed | Phase 3 | 122 |
| NCT00723190 | Open-Label, Chronic Exposure, Safety Study of CLONICEL (Clonidine HCl Sustained Release) in Children and Adolescents With Attention Deficit Hyperactivity Disorder (ADHD) 2008 | completed | Phase 3 | 303 |
| NCT04278404 | Pharmacokinetics, Pharmacodynamics, and Safety Profile of Understudied Drugs Administered to Children Per Standard of Care (POPS) 2020 | recruiting | Not applicable | 5,000 |
Published literature
- Clinical trial publication Efficacy and Safety of Extended-Release Clonidine Hydrochloride for Attention Deficit Hyperactivity Disorder in Chinese Children and Adolescents: A Multicenter, Randomized, Double-Blind, Placebo-Controlled TrialQian Y, Ke X, Gao F et al. · Journal of child and adolescent psychopharmacology · 2026 · PMID 41944053
- Cochrane review An Evaluation on the Efficacy and Safety of Treatments for Attention Deficit Hyperactivity Disorder in Children and Adolescents: a Comparison of Multiple TreatmentsLi Y, Gao J, He S et al. · Molecular neurobiology · 2017 · PMID 27738872
- Clinical trial publication Clonidine extended-release tablets as add-on therapy to psychostimulants in children and adolescents with ADHDKollins SH, Jain R, Brams M et al. · Pediatrics · 2011 · PMID 21555501
- Clinical trial publication Clonidine extended-release tablets for pediatric patients with attention-deficit/hyperactivity disorderJain R, Segal S, Kollins SH et al. · Journal of the American Academy of Child and Adolescent Psychiatry · 2011 · PMID 21241954
Mechanism and notes
Recorded mechanism or class: agonist; agonist.
OSMF's existing evidence tier for this pair is A (Strong), derived from the strength of the disease association recorded in DGIdb, in this case via the biomarker or target ADRA2C. The tier describes how well the drug-disease link is documented, not how well the drug works.
Frequently asked questions
Is Clonidine Hydrochloride approved for ADHD?
Clonidine Hydrochloride has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in ADHD would be drug repurposing rather than first-in-human development. This does not mean it is approved for ADHD. Approval status for the specific indication should always be confirmed with the relevant regulator and prescribing information.
Is Clonidine Hydrochloride in clinical trials for ADHD?
ClinicalTrials.gov lists 8 registered trials linking Clonidine Hydrochloride to ADHD: 2 are currently recruiting; 1 is active or not yet recruiting; 4 have completed; 1 is terminated, withdrawn, suspended or of unknown status. The most advanced is Phase 4 (NCT05916339). The largest enrolment is 5000 participants (NCT04278404). Registration activity spans 1999 to 2025.
What does the evidence show for Clonidine Hydrochloride in ADHD?
Clonidine Hydrochloride has both completed registered trials and synthesis-level publications linked to ADHD. That is the strongest profile in this database, but the summaries here do not extract effect sizes, so read the linked reviews for direction and magnitude of benefit. OSMF's existing evidence tier for this pair is A (Strong), derived from the strength of the disease association recorded in DGIdb, in this case via the biomarker or target ADRA2C. The tier describes how well the drug-disease link is documented, not how well the drug works.
Cite this page
Data: ClinicalTrials.gov, PubMed, Open Targets, ChEMBL, DGIdb and the OSMF therapeutic agent database. Last updated 2026-07-05. Page built 2026-10-07.