Drug interactions
Amlodipine-olmesartan-hydrochlorothiazide + Phenytoin
Severity: Moderate
Amlodipine-olmesartan-hydrochlorothiazide 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 may lower amlodipine concentrations by inducing CYP3A4, reducing blood pressure control. Amlodipine has been reported to raise phenytoin levels only rarely, so the main concern is reduced antihypertensive effect, with possible phenytoin toxicity.
What this interaction means in plain words
Amlodipine-olmesartan-hydrochlorothiazide 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-olmesartan-hydrochlorothiazide belongs to Cardiovascular; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4, increasing amlodipine metabolism; amlodipine may weakly inhibit phenytoin metabolism.
What to do
Monitor blood pressure and adjust the antihypertensive regimen if control is lost. Check phenytoin levels and signs of toxicity 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-olmesartan-hydrochlorothiazide
- Aliskiren + Amlodipine-olmesartan-hydrochlorothiazide Contraindicated
- Amlodipine-olmesartan-hydrochlorothiazide + Dofetilide Contraindicated
- Amlodipine-olmesartan-hydrochlorothiazide + Sparsentan Contraindicated
- Acemetacin + Amlodipine-olmesartan-hydrochlorothiazide Major
- Aldesleukin + Amlodipine-olmesartan-hydrochlorothiazide Major
- Amifostine + Amlodipine-olmesartan-hydrochlorothiazide 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-olmesartan-hydrochlorothiazide with Phenytoin?
MediHelp rates the interaction as moderate. Amlodipine-olmesartan-hydrochlorothiazide 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 may lower amlodipine concentrations by inducing CYP3A4, reducing blood pressure control. Amlodipine has been reported to raise phenytoin levels only rarely, so the main concern is reduced antihypertensive effect, with possible phenytoin toxicity.
How serious is the interaction between Amlodipine-olmesartan-hydrochlorothiazide 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 adjust the antihypertensive regimen if control is lost. Check phenytoin levels and signs of toxicity when starting or stopping amlodipine.
What other medicines interact with Amlodipine-olmesartan-hydrochlorothiazide?
MediHelp also lists interactions of Amlodipine-olmesartan-hydrochlorothiazide with, for example, Aliskiren, Dofetilide, Sparsentan. The full list is on the Amlodipine-olmesartan-hydrochlorothiazide page.
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