Drug interactions
Guanfacine + Quetiapine
Severity: Moderate
Guanfacine and Quetiapine: 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
Both drugs lower blood pressure and cause sedation, so combined use can lead to hypotension, dizziness, syncope and bradycardia. The effect is most notable at initiation or after dose increases.
What this interaction means in plain words
Guanfacine and Quetiapine 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.
Guanfacine belongs to Cardiovascular; Quetiapine belongs to Central Nervous System.
Why it happens
Additive hypotensive and sedative effects: central alpha-2 agonism by guanfacine plus alpha-1 blockade and sedation by quetiapine.
What to do
Monitor blood pressure and heart rate, titrate both drugs slowly, and advise patients to rise slowly. Do not stop guanfacine abruptly because of rebound hypertension.
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 Quetiapine
- Adagrasib + Quetiapine Major
- Amiodarone + Quetiapine Major
- Amisulpride + Quetiapine Major
- Amoxapine + Quetiapine Major
- Anagrelide + Quetiapine Major
- Apalutamide + Quetiapine Major
Other interactions of Guanfacine
- Clonidine + Guanfacine Major
- Guanfacine + Lofexidine Major
- Aldesleukin + Guanfacine Moderate
- Amiodarone + Guanfacine Moderate
- Amisulpride + Guanfacine Moderate
- Amitriptyline + Guanfacine Moderate
Frequently asked questions
Can I take Guanfacine with Quetiapine?
MediHelp rates the interaction as moderate. Guanfacine and Quetiapine 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. Both drugs lower blood pressure and cause sedation, so combined use can lead to hypotension, dizziness, syncope and bradycardia. The effect is most notable at initiation or after dose increases.
How serious is the interaction between Guanfacine and Quetiapine?
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, titrate both drugs slowly, and advise patients to rise slowly. Do not stop guanfacine abruptly because of rebound hypertension.
What other medicines interact with Quetiapine?
MediHelp also lists interactions of Quetiapine with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Quetiapine page.
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