Drug interactions
Losartan + Phenobarbital
Severity: Minor
Losartan and Phenobarbital: minor 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 hepatic CYP enzymes and may lower plasma levels of losartan and its active metabolite. This could reduce blood pressure control.
What this interaction means in plain words
Losartan and Phenobarbital have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Induction of CYP2C9 and CYP3A4 increasing losartan clearance.
What to do
Monitor blood pressure after starting or stopping phenobarbital and adjust the losartan dose as needed.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Losartan
- Aliskiren + Losartan Contraindicated
- Losartan + Sparsentan Contraindicated
- Amifostine + Losartan Major
- Amiloride + Losartan Major
- Amlodipine-benazepril + Losartan Major
- Amlodipine-hydrochlorothiazide-valsartan + Losartan Major
Frequently asked questions
Can I take Losartan with Phenobarbital?
MediHelp rates the interaction as minor. Losartan and Phenobarbital have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Phenobarbital induces hepatic CYP enzymes and may lower plasma levels of losartan and its active metabolite. This could reduce blood pressure control.
How serious is the interaction between Losartan and Phenobarbital?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure after starting or stopping phenobarbital and adjust the losartan dose as needed.
What other medicines interact with Losartan?
MediHelp also lists interactions of Losartan with, for example, Aliskiren, Sparsentan, Amifostine. The full list is on the Losartan page.
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