Drug interactions
Captopril-hydrochlorothiazide + Thioridazine
Severity: Major
Captopril-hydrochlorothiazide and Thioridazine: 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
Thioridazine can cause orthostatic hypotension, which may add to the effect of the antihypertensive combination. In addition, thiazide-induced hypokalemia or hypomagnesemia increases the risk of QT prolongation and torsades de pointes with thioridazine, which is a more serious concern.
What this interaction means in plain words
Captopril-hydrochlorothiazide and Thioridazine 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.
Captopril-hydrochlorothiazide belongs to Cardiovascular; Thioridazine belongs to Central Nervous System.
Why it happens
Additive hypotension from alpha-blockade, and diuretic-induced electrolyte loss that potentiates thioridazine QT prolongation.
What to do
Check and correct potassium and magnesium before and during therapy, and monitor ECG and blood pressure. Consider an alternative antipsychotic with less QT effect.
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?
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Other interactions of Captopril-hydrochlorothiazide
- Aliskiren + Captopril-hydrochlorothiazide Contraindicated
- Captopril-hydrochlorothiazide + Dofetilide Contraindicated
- Captopril-hydrochlorothiazide + Sacubitril / valsartan Contraindicated
- Aceclofenac + Captopril-hydrochlorothiazide Major
- Aldesleukin + Captopril-hydrochlorothiazide Major
- Amifostine + Captopril-hydrochlorothiazide Major
Other interactions of Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Frequently asked questions
Can I take Captopril-hydrochlorothiazide with Thioridazine?
MediHelp rates the interaction as major. Captopril-hydrochlorothiazide and Thioridazine 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. Thioridazine can cause orthostatic hypotension, which may add to the effect of the antihypertensive combination. In addition, thiazide-induced hypokalemia or hypomagnesemia increases the risk of QT prolongation and torsades de pointes with thioridazine, which is a more serious concern.
How serious is the interaction between Captopril-hydrochlorothiazide and Thioridazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check and correct potassium and magnesium before and during therapy, and monitor ECG and blood pressure. Consider an alternative antipsychotic with less QT effect.
What other medicines interact with Captopril-hydrochlorothiazide?
MediHelp also lists interactions of Captopril-hydrochlorothiazide with, for example, Aliskiren, Dofetilide, Sacubitril / valsartan. The full list is on the Captopril-hydrochlorothiazide page.
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