Drug interactions
Nimodipine + Phenytoin
Severity: Major
Nimodipine and Phenytoin: major 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 strongly induces CYP3A4 and markedly lowers nimodipine exposure in studies, which may cause loss of effect. Nimodipine may also affect phenytoin levels in some reports.
What this interaction means in plain words
Nimodipine and Phenytoin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Nimodipine belongs to Cardiovascular; Phenytoin belongs to Central Nervous System.
Why it happens
Induction of CYP3A4 by phenytoin increasing nimodipine first-pass and systemic metabolism.
What to do
Avoid the combination where possible, as nimodipine efficacy may be lost; if used, monitor response closely and check phenytoin levels.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Nimodipine and Phenytoin, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Nimodipine
- Apalutamide + Nimodipine Major
- Carbamazepine + Nimodipine Major
- Ceritinib + Nimodipine Major
- Clarithromycin + Nimodipine Major
- Cobicistat + Nimodipine Major
- Darunavir + Nimodipine 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 Nimodipine with Phenytoin?
MediHelp rates the interaction as major. Nimodipine and Phenytoin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Phenytoin strongly induces CYP3A4 and markedly lowers nimodipine exposure in studies, which may cause loss of effect. Nimodipine may also affect phenytoin levels in some reports.
How serious is the interaction between Nimodipine and Phenytoin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible, as nimodipine efficacy may be lost; if used, monitor response closely and check phenytoin levels.
What other medicines interact with Nimodipine?
MediHelp also lists interactions of Nimodipine with, for example, Apalutamide, Carbamazepine, Ceritinib. The full list is on the Nimodipine page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
