Drug interactions
Fosinopril-hydrochlorothiazide + Promethazine
Severity: Minor
Fosinopril-hydrochlorothiazide and Promethazine: 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
Promethazine has sedative and mild alpha-blocking properties that can add to the blood pressure lowering of an ACE inhibitor and thiazide. Dizziness and orthostatic hypotension may result, especially in older adults.
What this interaction means in plain words
Fosinopril-hydrochlorothiazide and Promethazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Fosinopril-hydrochlorothiazide belongs to Cardiovascular; Promethazine belongs to Respiratory.
Why it happens
Additive hypotensive effect from phenothiazine alpha-adrenergic blockade.
What to do
Monitor blood pressure and advise slow postural changes when promethazine is started or the dose is raised.
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 Fosinopril-hydrochlorothiazide
- Aliskiren + Fosinopril-hydrochlorothiazide Contraindicated
- Dofetilide + Fosinopril-hydrochlorothiazide Contraindicated
- Fosinopril-hydrochlorothiazide + Protein a column Contraindicated
- Fosinopril-hydrochlorothiazide + Sacubitril / valsartan Contraindicated
- Aldesleukin + Fosinopril-hydrochlorothiazide Major
- Amifostine + Fosinopril-hydrochlorothiazide Major
Other interactions of Promethazine
- Cabergoline + Promethazine Contraindicated
- Dopamine + Promethazine Contraindicated
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
Frequently asked questions
Can I take Fosinopril-hydrochlorothiazide with Promethazine?
MediHelp rates the interaction as minor. Fosinopril-hydrochlorothiazide and Promethazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Promethazine has sedative and mild alpha-blocking properties that can add to the blood pressure lowering of an ACE inhibitor and thiazide. Dizziness and orthostatic hypotension may result, especially in older adults.
How serious is the interaction between Fosinopril-hydrochlorothiazide and Promethazine?
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 and advise slow postural changes when promethazine is started or the dose is raised.
What other medicines interact with Fosinopril-hydrochlorothiazide?
MediHelp also lists interactions of Fosinopril-hydrochlorothiazide with, for example, Aliskiren, Dofetilide, Protein a column. The full list is on the Fosinopril-hydrochlorothiazide page.
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