Drug interactions
Guanfacine + Olanzapine
Severity: Moderate
Guanfacine and Olanzapine: 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
Guanfacine lowers blood pressure and heart rate and causes sedation, while olanzapine can cause orthostatic hypotension and sedation. Combined use may increase dizziness, syncope and somnolence.
What this interaction means in plain words
Guanfacine and Olanzapine 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; Olanzapine belongs to Central Nervous System.
Why it happens
Additive hypotensive and sedative effects: central alpha-2 agonism with alpha-1 adrenergic blockade.
What to do
Monitor blood pressure, heart rate and sedation, particularly when starting or increasing either drug. Advise patients to rise slowly and adjust doses if symptomatic hypotension occurs.
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 Olanzapine
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 Olanzapine?
MediHelp rates the interaction as moderate. Guanfacine and Olanzapine 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 lowers blood pressure and heart rate and causes sedation, while olanzapine can cause orthostatic hypotension and sedation. Combined use may increase dizziness, syncope and somnolence.
How serious is the interaction between Guanfacine and Olanzapine?
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, heart rate and sedation, particularly when starting or increasing either drug. Advise patients to rise slowly and adjust doses if symptomatic hypotension occurs.
What other medicines interact with Olanzapine?
MediHelp also lists interactions of Olanzapine with, for example, Amisulpride, Amoxapine, Apomorphine. The full list is on the Olanzapine page.
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