Drug interactions
Fosinopril-hydrochlorothiazide + Tolvaptan
Severity: Moderate
Fosinopril-hydrochlorothiazide and Tolvaptan: 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
Tolvaptan is an aquaretic and combined with a thiazide can cause excessive fluid loss, volume depletion and hypotension. Rapid shifts in serum sodium and potassium are also possible, and ACE inhibitors increase the risk of renal impairment when volume depleted.
What this interaction means in plain words
Fosinopril-hydrochlorothiazide and Tolvaptan 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.
Fosinopril-hydrochlorothiazide belongs to Cardiovascular; Tolvaptan belongs to Endocrine.
Why it happens
Vasopressin V2 antagonism causes free water excretion that adds to diuretic-induced volume and electrolyte changes.
What to do
Monitor serum sodium, potassium, volume status and renal function closely, especially at initiation. Avoid fluid restriction beyond what is intended.
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 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 Tolvaptan
- Atazanavir + Tolvaptan Contraindicated
- Ceritinib + Tolvaptan Contraindicated
- Cobicistat + Tolvaptan Contraindicated
- Conivaptan + Tolvaptan Contraindicated
- Darunavir + Tolvaptan Contraindicated
- Idelalisib + Tolvaptan Contraindicated
Frequently asked questions
Can I take Fosinopril-hydrochlorothiazide with Tolvaptan?
MediHelp rates the interaction as moderate. Fosinopril-hydrochlorothiazide and Tolvaptan 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. Tolvaptan is an aquaretic and combined with a thiazide can cause excessive fluid loss, volume depletion and hypotension. Rapid shifts in serum sodium and potassium are also possible, and ACE inhibitors increase the risk of renal impairment when volume depleted.
How serious is the interaction between Fosinopril-hydrochlorothiazide and Tolvaptan?
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 sodium, potassium, volume status and renal function closely, especially at initiation. Avoid fluid restriction beyond what is intended.
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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