Clonidine
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Clonidine: From Hypertension to Faciodigitogenital Syndrome
One-Sentence Summary
Clonidine is a centrally acting alpha-2 adrenergic agonist, originally used to treat hypertension, open-angle glaucoma and attention deficit hyperactivity disorder (ADHD). The TxGNN model’s top-ranked prediction is faciodigitogenital syndrome, but it has no supporting studies. The best-supported prediction is Tourette syndrome, with 2 clinical trials and 19 publications, including a European guideline and a network meta-analysis. This report covers Tourette syndrome as the prediction with the strongest evidence. Other candidates are summarized briefly where relevant.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Hypertension, open-angle glaucoma, ADHD (the Canadian license records contain no indication text) |
| Predicted New Indication | Top-ranked by TxGNN: faciodigitogenital syndrome (no evidence, L5, Hold). Best-supported: Tourette syndrome |
| TxGNN Prediction Score | 0.9998 for Tourette syndrome (1.0000 for the top-ranked faciodigitogenital syndrome) |
| Evidence Level | L5 (Tourette syndrome) |
| Canada Market Status | Marketed (marketed DINs: 14 of 14) |
| Number of DINs | 14 (marketed: 14) |
| Recommended Decision | Proceed with Guardrails (Tourette syndrome) |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. Based on known information, clonidine is an alpha-2 adrenergic agonist. It reduces noradrenergic tone, which is the basis of its use in hypertension and ADHD.
Tourette syndrome is a neurodevelopmental tic disorder that frequently occurs together with ADHD. Reduced noradrenergic activity in prefrontal-striatal circuits is thought to ease both tics and ADHD symptoms. Clonidine is already named as a treatment option in the 2022 European clinical guidelines for tic disorders, and a 2023 network meta-analysis supports its use. Because the original ADHD indication overlaps closely with Tourette syndrome, this is a practical label-expansion candidate.
The other predictions are weaker:
- Specific developmental disorder (L4, Hold): plausible given clonidine’s ADHD use, but the evidence is reviews and a mouse study, and the category is heterogeneous.
- Manic bipolar disorder (L3, Research Question): a 2023 systematic review and a 2022 randomized adjuvant study exist, but the only registered trial was terminated with 5 participants.
- Migraine (L3, Research Question): older small studies only, and a 2023 meta-analysis does not make clonidine a recommended option.
- Obesity (L3, Research Question): the trials are mechanistic studies of obesity-related hypertension and inflammation, not weight-loss trials.
- Trichotillomania (L5, Hold): only indirect mouse data.
- Faciodigitogenital syndrome, chondromyxoid fibroma, hypervitaminosis and proximal 16p11.2 microdeletion syndrome (L5, Hold): prediction only, with no trials or literature and no evident mechanistic rationale.
Clinical Trial Evidence
Tourette syndrome:
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT00370838 | Phase 4 | Completed | 12 | Levetiracetam vs clonidine for tics in children with Tourette syndrome (crossover design); directly relevant but very small |
| NCT00152750 | Phase 4 | Unknown | 32 | Whether night-time clonidine improves day-time aggression in children with Tourette syndrome and comorbid ADHD; targets aggression rather than tics |
Trials for other predicted indications:
| Trial Number | Indication | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|---|
| NCT01983462 | Obesity | Phase 2 | Terminated | 33 | Effect of sympathetic blockade with clonidine on vascular function in obese hypertensive adults |
| NCT04934228 | Obesity | Phase 1 | Recruiting | 60 | Oral clonidine for 4 weeks to reduce inflammatory markers in obesity; no results yet |
| NCT03065933 | Manic bipolar disorder | Phase 4 | Terminated | 5 | Open-label add-on extended-release clonidine as an anti-manic agent; negligible evidence |
Literature Evidence
Tourette syndrome (selected from 19 retrieved publications):
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 34757514 | 2022 | Clinical guideline | Eur Child Adolesc Psychiatry | European guidelines (version 2.0) on pharmacological treatment of Tourette syndrome and tic disorders |
| 36528030 | 2023 | Network meta-analysis | Lancet Child Adolesc Health | Compares efficacy, tolerability and acceptability of drugs for Tourette syndrome in young people |
| 38695046 | 2024 | Clinical study | Psychiatry Investigation | Efficacy and safety of the clonidine patch in Tourette syndrome with comorbid ADHD |
| 23473832 | 2013 | Review | Eur J Paediatr Neurol | Pharmacological options for Tourette syndrome with comorbid ADHD |
| 31061209 | 2019 | Systematic review | Neurology | Systematic review of tic treatments (retrieved under the broader developmental-disorder prediction) |
| 34286606 | 2021 | Systematic review | J Psychopharmacol | Assesses the quality of evidence for Tourette syndrome drug treatments |
| 27132945 | 2016 | Systematic review | J Child Psychol Psychiatry | Treatments for Tourette syndrome in children and young people |
| 89558 | 1979 | Early clinical study | Lancet | Small doses of clonidine improved some children unresponsive to haloperidol |
Canada Market Information
Health Canada lists 14 valid single-ingredient authorizations for clonidine and no cancelled ones. Dosage form, manufacturer and approved indication text are not available for these records. Five are shown:
| DIN | Product Name |
|---|---|
| 02046148 | TEVA-CLONIDINE |
| 02538490 | CLONIDINE |
| 02516217 | SANDOZ CLONIDINE |
| 02304163 | TEVA-CLONIDINE |
| 02524198 | MAR-CLONIDINE |
Safety Considerations
- Drug Interactions: 100 interactions were found, and all 20 listed in the data are rated Moderate.
- Corticosteroids: hydrocortisone, triamcinolone, dexamethasone, betamethasone, budesonide
- Diabetes medicines: insulin products, sulfonylureas (chlorpropamide, acetohexamide, glimepiride, glipizide, glyburide) and SGLT2 inhibitors (canagliflozin, dapagliflozin, empagliflozin, ertugliflozin)
- Others: bupropion, morphine, dronabinol
- Knowledge-graph contraindication signals (from the TxGNN knowledge graph, not label text): liver failure, anxiety and neurotic disorders, pancreatitis, systemic lupus erythematosus, hypotensive disorder, anuria, gout, myocardial infarction and ischemia, heart conduction disease, sudden cardiac arrest, respiratory failure, type 1 and type 2 diabetes, diabetic ketoacidosis, and several electrolyte or metabolic disorders. These need verification against the Canadian product monograph.
- Population guardrails: hypotension, bradycardia and sedation are expected concerns, particularly in children and in psychiatric populations.
Please refer to the package insert for the official warnings and contraindications.
Conclusion and Next Steps
Decision: Proceed with Guardrails (Tourette syndrome)
Rationale:
- Clonidine is already guideline-listed for tic disorders, and a network meta-analysis supports it. The only trials are small Phase 4 studies (n=12 and n=32), so the evidence is L3 rather than pivotal.
- The other predictions remain at Hold or Research Question, and the top-ranked prediction has no supporting evidence.
To proceed, the following is needed:
- Health Canada product monograph warnings and contraindications (a blocking gap for safety screening)
- Mechanism of action data from DrugBank
- A review of clonidine’s place in Tourette syndrome treatment from the guideline and meta-analysis, including comparison with approved alternatives
- Approved indication text and dosage forms for the Canadian authorizations, to confirm whether a label expansion would be needed
- A safety monitoring plan for blood pressure, heart rate and sedation, especially in children, and for patients with diabetes or cardiac conduction disease
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.