Drug interactions
Hydrochlorothiazide-losartan + Quinidine
Severity: Moderate
Hydrochlorothiazide-losartan and Quinidine: 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
Quinidine may compete with hydrochlorothiazide for renal tubular secretion, but the clinical effect is minor. Thiazide-induced hypokalemia or hypomagnesemia can increase quinidine-related QT prolongation and torsades de pointes risk, which is the more important concern.
What this interaction means in plain words
Hydrochlorothiazide-losartan and Quinidine 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.
Hydrochlorothiazide-losartan belongs to Cardiovascular; Quinidine belongs to Anti Parasitic.
Why it happens
Thiazide-induced hypokalemia and hypomagnesemia potentiate quinidine QT prolongation, with minor renal transport competition.
What to do
Monitor serum potassium and magnesium and correct deficits; obtain an ECG when starting or adjusting therapy.
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
Other interactions of Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine Contraindicated
Frequently asked questions
Can I take Hydrochlorothiazide-losartan with Quinidine?
MediHelp rates the interaction as moderate. Hydrochlorothiazide-losartan and Quinidine 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. Quinidine may compete with hydrochlorothiazide for renal tubular secretion, but the clinical effect is minor. Thiazide-induced hypokalemia or hypomagnesemia can increase quinidine-related QT prolongation and torsades de pointes risk, which is the more important concern.
How serious is the interaction between Hydrochlorothiazide-losartan and Quinidine?
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 serum potassium and magnesium and correct deficits; obtain an ECG when starting or adjusting therapy.
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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