Drug interactions
Hydrochlorothiazide-losartan + Pentobarbital
Severity: Moderate
Hydrochlorothiazide-losartan and Pentobarbital: 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
Barbiturates induce hepatic enzymes including CYP2C9 and may reduce conversion of losartan to active metabolite and lower its exposure, weakening blood pressure control. Barbiturates may also add to orthostatic hypotension with thiazides.
What this interaction means in plain words
Hydrochlorothiazide-losartan and Pentobarbital 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
Barbiturate induction of CYP2C9 and related enzymes increases losartan metabolism, plus additive hypotensive effect.
What to do
Monitor blood pressure when pentobarbital is started or stopped, and warn patients about orthostatic dizziness.
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 Hydrochlorothiazide-losartan
- Aliskiren + Hydrochlorothiazide-losartan Contraindicated
- Dofetilide + Hydrochlorothiazide-losartan Contraindicated
- Hydrochlorothiazide-losartan + Sparsentan Contraindicated
- Aceclofenac + Hydrochlorothiazide-losartan Major
- Aldesleukin + Hydrochlorothiazide-losartan Major
- Amifostine + Hydrochlorothiazide-losartan Major
Frequently asked questions
Can I take Hydrochlorothiazide-losartan with Pentobarbital?
MediHelp rates the interaction as moderate. Hydrochlorothiazide-losartan and Pentobarbital 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. Barbiturates induce hepatic enzymes including CYP2C9 and may reduce conversion of losartan to active metabolite and lower its exposure, weakening blood pressure control. Barbiturates may also add to orthostatic hypotension with thiazides.
How serious is the interaction between Hydrochlorothiazide-losartan and Pentobarbital?
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 pentobarbital is started or stopped, and warn patients about orthostatic dizziness.
What other medicines interact with Hydrochlorothiazide-losartan?
MediHelp also lists interactions of Hydrochlorothiazide-losartan with, for example, Aliskiren, Dofetilide, Sparsentan. The full list is on the Hydrochlorothiazide-losartan page.
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