Drug interactions
Hydrochlorothiazide-olmesartan + Sulfamethoxazole
Severity: Moderate
Hydrochlorothiazide-olmesartan 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-trimethoprim can cause hyponatremia, and thiazides also cause sodium loss, so the combined risk is increased especially in older adults. Trimethoprim also raises potassium, which matters with olmesartan because of added hyperkalemia risk.
What this interaction means in plain words
Hydrochlorothiazide-olmesartan 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 sodium loss from thiazide and trimethoprim, and potassium retention from trimethoprim combined with angiotensin receptor blockade.
What to do
Check serum sodium, potassium and creatinine within the first week of co-trimoxazole therapy, especially in elderly or renally impaired patients, and consider an alternative antibiotic if abnormalities develop.
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-olmesartan
- Aliskiren + Hydrochlorothiazide-olmesartan Contraindicated
- Dofetilide + Hydrochlorothiazide-olmesartan Contraindicated
- Hydrochlorothiazide-olmesartan + Sparsentan Contraindicated
- Acemetacin + Hydrochlorothiazide-olmesartan Major
- Amifostine + Hydrochlorothiazide-olmesartan Major
- Amiloride + Hydrochlorothiazide-olmesartan Major
Frequently asked questions
Can I take Hydrochlorothiazide-olmesartan with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Hydrochlorothiazide-olmesartan 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-trimethoprim can cause hyponatremia, and thiazides also cause sodium loss, so the combined risk is increased especially in older adults. Trimethoprim also raises potassium, which matters with olmesartan because of added hyperkalemia risk.
How serious is the interaction between Hydrochlorothiazide-olmesartan 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: Check serum sodium, potassium and creatinine within the first week of co-trimoxazole therapy, especially in elderly or renally impaired patients, and consider an alternative antibiotic if abnormalities develop.
What other medicines interact with Hydrochlorothiazide-olmesartan?
MediHelp also lists interactions of Hydrochlorothiazide-olmesartan with, for example, Aliskiren, Dofetilide, Sparsentan. The full list is on the Hydrochlorothiazide-olmesartan page.
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