Drug interactions
Guanfacine + Rifampicin
Severity: Moderate
Guanfacine and Rifampicin: 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
Rifampicin markedly lowers guanfacine concentrations, which can reduce its therapeutic effect in ADHD or hypertension.
What this interaction means in plain words
Guanfacine and Rifampicin 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; Rifampicin belongs to Anti Bacterial.
Why it happens
Rifampicin induces CYP3A4, increasing guanfacine clearance.
What to do
Consider increasing the guanfacine dose, up to double, guided by clinical response. Reduce it again over 1 to 2 weeks after rifampicin is stopped.
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 Guanfacine
- Clonidine + Guanfacine Major
- Guanfacine + Lofexidine Major
- Aldesleukin + Guanfacine Moderate
- Amiodarone + Guanfacine Moderate
- Amisulpride + Guanfacine Moderate
- Amitriptyline + Guanfacine Moderate
Other interactions of Rifampicin
- Cabotegravir + Rifampicin Contraindicated
- Delamanid + Rifampicin Contraindicated
- Doravirine + Rifampicin Contraindicated
- Ensitrelvir + Rifampicin Contraindicated
- Fostemsavir + Rifampicin Contraindicated
- Isavuconazole + Rifampicin Contraindicated
Frequently asked questions
Can I take Guanfacine with Rifampicin?
MediHelp rates the interaction as moderate. Guanfacine and Rifampicin 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. Rifampicin markedly lowers guanfacine concentrations, which can reduce its therapeutic effect in ADHD or hypertension.
How serious is the interaction between Guanfacine and Rifampicin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Consider increasing the guanfacine dose, up to double, guided by clinical response. Reduce it again over 1 to 2 weeks after rifampicin is stopped.
What other medicines interact with Guanfacine?
MediHelp also lists interactions of Guanfacine with, for example, Clonidine, Lofexidine, Aldesleukin. The full list is on the Guanfacine page.
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