Drug interactions
Amlodipine-hydrochlorothiazide-valsartan + Phenobarbital
Severity: Moderate
Amlodipine-hydrochlorothiazide-valsartan and Phenobarbital: 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
Phenobarbital induces CYP3A4 and can lower amlodipine concentrations, reducing antihypertensive efficacy. Additive hypotension and sedation may also occur.
What this interaction means in plain words
Amlodipine-hydrochlorothiazide-valsartan and Phenobarbital 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.
Why it happens
Enzyme induction of CYP3A4 increases amlodipine clearance.
What to do
Monitor blood pressure when phenobarbital is started, changed or stopped. Increase the amlodipine dose or choose another agent if control is inadequate.
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 Amlodipine-hydrochlorothiazide-valsartan
- Aliskiren + Amlodipine-hydrochlorothiazide-valsartan Contraindicated
- Amlodipine-hydrochlorothiazide-valsartan + Dofetilide Contraindicated
- Amlodipine-hydrochlorothiazide-valsartan + Sparsentan Contraindicated
- Aceclofenac + Amlodipine-hydrochlorothiazide-valsartan Major
- Aldesleukin + Amlodipine-hydrochlorothiazide-valsartan Major
- Amifostine + Amlodipine-hydrochlorothiazide-valsartan Major
Frequently asked questions
Can I take Amlodipine-hydrochlorothiazide-valsartan with Phenobarbital?
MediHelp rates the interaction as moderate. Amlodipine-hydrochlorothiazide-valsartan and Phenobarbital 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. Phenobarbital induces CYP3A4 and can lower amlodipine concentrations, reducing antihypertensive efficacy. Additive hypotension and sedation may also occur.
How serious is the interaction between Amlodipine-hydrochlorothiazide-valsartan and Phenobarbital?
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 when phenobarbital is started, changed or stopped. Increase the amlodipine dose or choose another agent if control is inadequate.
What other medicines interact with Amlodipine-hydrochlorothiazide-valsartan?
MediHelp also lists interactions of Amlodipine-hydrochlorothiazide-valsartan with, for example, Aliskiren, Dofetilide, Sparsentan. The full list is on the Amlodipine-hydrochlorothiazide-valsartan page.
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