Drug interactions
Amitriptyline + Guanfacine
Severity: Moderate
Amitriptyline and Guanfacine: moderate 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
Tricyclics may blunt the antihypertensive effect of centrally acting alpha-2 agonists. Both drugs also cause sedation and may cause orthostatic hypotension or bradycardia.
What this interaction means in plain words
Amitriptyline and Guanfacine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Amitriptyline belongs to Central Nervous System; Guanfacine belongs to Cardiovascular.
Why it happens
Tricyclics may antagonize alpha-2 agonist action, and there is additive sedative and hypotensive pharmacodynamic effect.
What to do
Monitor blood pressure and heart rate and adjust guanfacine as required. Monitor for sedation and dizziness.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Other interactions of Guanfacine
- Clonidine + Guanfacine Major
- Guanfacine + Lofexidine Major
- Aldesleukin + Guanfacine Moderate
- Amiodarone + Guanfacine Moderate
- Amisulpride + Guanfacine Moderate
- Amobarbital + Guanfacine Moderate
Frequently asked questions
Can I take Amitriptyline with Guanfacine?
MediHelp rates the interaction as moderate. Amitriptyline and Guanfacine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Tricyclics may blunt the antihypertensive effect of centrally acting alpha-2 agonists. Both drugs also cause sedation and may cause orthostatic hypotension or bradycardia.
How serious is the interaction between Amitriptyline and Guanfacine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure and heart rate and adjust guanfacine as required. Monitor for sedation and dizziness.
What other medicines interact with Amitriptyline?
MediHelp also lists interactions of Amitriptyline with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Amitriptyline page.
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