Drug interactions
Guanfacine + Posaconazole
Severity: Moderate
Guanfacine and Posaconazole: 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
Posaconazole can substantially increase guanfacine concentrations, raising the risk of hypotension, bradycardia and sedation.
What this interaction means in plain words
Guanfacine and Posaconazole 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; Posaconazole belongs to Anti Fungals.
Why it happens
Strong CYP3A4 inhibition decreases guanfacine clearance.
What to do
Halve the dose of extended-release guanfacine during posaconazole therapy. Monitor blood pressure, heart rate and sedation, and consider a similar reduction for immediate-release.
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 Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
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 Posaconazole?
MediHelp rates the interaction as moderate. Guanfacine and Posaconazole 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. Posaconazole can substantially increase guanfacine concentrations, raising the risk of hypotension, bradycardia and sedation.
How serious is the interaction between Guanfacine and Posaconazole?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Halve the dose of extended-release guanfacine during posaconazole therapy. Monitor blood pressure, heart rate and sedation, and consider a similar reduction for immediate-release.
What other medicines interact with Posaconazole?
MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.
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