Drug interactions
Captopril + Phenobarbital
Severity: Moderate
Captopril 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 may add to the blood pressure-lowering effect of captopril and cause orthostatic hypotension. The effect is usually modest at anticonvulsant maintenance doses.
What this interaction means in plain words
Captopril 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
Additive hypotensive effects of barbiturate-induced CNS depression and vasodilation with ACE inhibition.
What to do
Monitor blood pressure when starting or changing either drug and reduce the antihypertensive dose if hypotension develops.
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 Captopril
- Aliskiren + Captopril Contraindicated
- Captopril + Sacubitril / valsartan Contraindicated
- Captopril + Sacubitril-valsartan Contraindicated
- Amifostine + Captopril Major
- Amiloride + Captopril Major
- Amlodipine-hydrochlorothiazide-valsartan + Captopril Major
Frequently asked questions
Can I take Captopril with Phenobarbital?
MediHelp rates the interaction as moderate. Captopril 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 may add to the blood pressure-lowering effect of captopril and cause orthostatic hypotension. The effect is usually modest at anticonvulsant maintenance doses.
How serious is the interaction between Captopril 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 starting or changing either drug and reduce the antihypertensive dose if hypotension develops.
What other medicines interact with Captopril?
MediHelp also lists interactions of Captopril with, for example, Aliskiren, Sacubitril / valsartan, Sacubitril-valsartan. The full list is on the Captopril page.
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