Drug interactions
Hydrochlorothiazide-valsartan + Sulfamethoxazole
Severity: Moderate
Hydrochlorothiazide-valsartan 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) combined with a thiazide and an angiotensin receptor blocker can cause hyponatremia, and trimethoprim with valsartan can also cause hyperkalemia. Older patients and those with renal impairment are at greater risk.
What this interaction means in plain words
Hydrochlorothiazide-valsartan 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 loss from the thiazide and trimethoprim's amiloride-like ENaC blockade, plus potassium retention with the ARB.
What to do
Monitor serum sodium, potassium and creatinine within the first week of co-trimoxazole therapy; consider an alternative antibiotic in high-risk 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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Hydrochlorothiazide-valsartan and Sulfamethoxazole, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Hydrochlorothiazide-valsartan
- Aliskiren + Hydrochlorothiazide-valsartan Contraindicated
- Dofetilide + Hydrochlorothiazide-valsartan Contraindicated
- Hydrochlorothiazide-valsartan + Sparsentan Contraindicated
- Aldesleukin + Hydrochlorothiazide-valsartan Major
- Amifostine + Hydrochlorothiazide-valsartan Major
- Amiloride + Hydrochlorothiazide-valsartan Major
Frequently asked questions
Can I take Hydrochlorothiazide-valsartan with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Hydrochlorothiazide-valsartan 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) combined with a thiazide and an angiotensin receptor blocker can cause hyponatremia, and trimethoprim with valsartan can also cause hyperkalemia. Older patients and those with renal impairment are at greater risk.
How serious is the interaction between Hydrochlorothiazide-valsartan 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 co-trimoxazole therapy; consider an alternative antibiotic in high-risk patients.
What other medicines interact with Hydrochlorothiazide-valsartan?
MediHelp also lists interactions of Hydrochlorothiazide-valsartan with, for example, Aliskiren, Dofetilide, Sparsentan. The full list is on the Hydrochlorothiazide-valsartan page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
