Drug interactions
Amlodipine-valsartan + Phenytoin
Severity: Moderate
Amlodipine-valsartan and Phenytoin: 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
Phenytoin is a CYP3A4 inducer and may lower amlodipine concentrations, reducing blood pressure control. Amlodipine has also been reported to affect phenytoin levels, although this is not well established.
What this interaction means in plain words
Amlodipine-valsartan and Phenytoin 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.
Amlodipine-valsartan belongs to Cardiovascular; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4, increasing amlodipine clearance; the effect of amlodipine on phenytoin is poorly characterized.
What to do
Monitor blood pressure and titrate amlodipine upward if control is lost. Check phenytoin levels or signs of toxicity (nystagmus, ataxia) when starting or stopping amlodipine.
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-valsartan
- Aliskiren + Amlodipine-valsartan Contraindicated
- Amlodipine-valsartan + Sparsentan Contraindicated
- Aldesleukin + Amlodipine-valsartan Major
- Amifostine + Amlodipine-valsartan Major
- Amiloride + Amlodipine-valsartan Major
- Amlodipine-valsartan + Benazepril Major
Other interactions of Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Frequently asked questions
Can I take Amlodipine-valsartan with Phenytoin?
MediHelp rates the interaction as moderate. Amlodipine-valsartan and Phenytoin 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. Phenytoin is a CYP3A4 inducer and may lower amlodipine concentrations, reducing blood pressure control. Amlodipine has also been reported to affect phenytoin levels, although this is not well established.
How serious is the interaction between Amlodipine-valsartan and Phenytoin?
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 titrate amlodipine upward if control is lost. Check phenytoin levels or signs of toxicity (nystagmus, ataxia) when starting or stopping amlodipine.
What other medicines interact with Amlodipine-valsartan?
MediHelp also lists interactions of Amlodipine-valsartan with, for example, Aliskiren, Sparsentan, Aldesleukin. The full list is on the Amlodipine-valsartan page.
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