Drug interactions
Hydrochlorothiazide-irbesartan + Sulfamethoxazole
Severity: Moderate
Hydrochlorothiazide-irbesartan and Sulfamethoxazole: 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
Sulfamethoxazole, usually with trimethoprim, can cause hyponatremia, and thiazides have the same effect. Combination with irbesartan also raises the risk of hyperkalemia and renal impairment when trimethoprim is present.
What this interaction means in plain words
Hydrochlorothiazide-irbesartan and Sulfamethoxazole 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
Additive effects on sodium handling; trimethoprim blocks distal sodium channels and adds to ARB potassium retention.
What to do
Monitor serum sodium, potassium and creatinine within the first week of therapy, especially in older patients.
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-irbesartan
- Aliskiren + Hydrochlorothiazide-irbesartan Contraindicated
- Dofetilide + Hydrochlorothiazide-irbesartan Contraindicated
- Hydrochlorothiazide-irbesartan + Sparsentan Contraindicated
- Aldesleukin + Hydrochlorothiazide-irbesartan Major
- Amifostine + Hydrochlorothiazide-irbesartan Major
- Amiloride + Hydrochlorothiazide-irbesartan Major
Frequently asked questions
Can I take Hydrochlorothiazide-irbesartan with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Hydrochlorothiazide-irbesartan and Sulfamethoxazole 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. Sulfamethoxazole, usually with trimethoprim, can cause hyponatremia, and thiazides have the same effect. Combination with irbesartan also raises the risk of hyperkalemia and renal impairment when trimethoprim is present.
How serious is the interaction between Hydrochlorothiazide-irbesartan and Sulfamethoxazole?
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 and creatinine within the first week of therapy, especially in older patients.
What other medicines interact with Hydrochlorothiazide-irbesartan?
MediHelp also lists interactions of Hydrochlorothiazide-irbesartan with, for example, Aliskiren, Dofetilide, Sparsentan. The full list is on the Hydrochlorothiazide-irbesartan page.
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