Drug interactions
Clonidine + Guanfacine
Severity: Major
Clonidine and Guanfacine: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both are central alpha-2 adrenergic agonists, so combining them duplicates therapy and increases the risk of hypotension, bradycardia and sedation. Patients with conduction disease may be at greater risk of heart block.
What this interaction means in plain words
Clonidine and Guanfacine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Clonidine belongs to Cardiovascular; Guanfacine belongs to Cardiovascular.
Why it happens
Additive central alpha-2 agonism reduces sympathetic outflow, causing pharmacodynamic synergism.
What to do
Avoid using both together unless there is a clear indication; if used, monitor heart rate, blood pressure and sedation closely. Taper one agent gradually when stopping to avoid rebound hypertension.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Clonidine
- Acebutolol + Clonidine Major
- Amifostine + Clonidine Major
- Amiodarone + Clonidine Major
- Amoxapine + Clonidine Major
- Atenolol-chlorthalidone + Clonidine Major
- Atenolol + Clonidine Major
Other interactions of Guanfacine
- Guanfacine + Lofexidine Major
- Aldesleukin + Guanfacine Moderate
- Amiodarone + Guanfacine Moderate
- Amisulpride + Guanfacine Moderate
- Amitriptyline + Guanfacine Moderate
- Amobarbital + Guanfacine Moderate
Frequently asked questions
Can I take Clonidine with Guanfacine?
MediHelp rates the interaction as major. Clonidine and Guanfacine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both are central alpha-2 adrenergic agonists, so combining them duplicates therapy and increases the risk of hypotension, bradycardia and sedation. Patients with conduction disease may be at greater risk of heart block.
How serious is the interaction between Clonidine and Guanfacine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid using both together unless there is a clear indication; if used, monitor heart rate, blood pressure and sedation closely. Taper one agent gradually when stopping to avoid rebound hypertension.
What other medicines interact with Clonidine?
MediHelp also lists interactions of Clonidine with, for example, Acebutolol, Amifostine, Amiodarone. The full list is on the Clonidine page.
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