Drug interactions
Hydrochlorothiazide-lisinopril + Trimethoprim
Severity: Moderate
Hydrochlorothiazide-lisinopril and Trimethoprim: 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
Trimethoprim reduces renal potassium excretion, and with an ACE inhibitor this can lead to significant hyperkalemia, especially in the elderly or those with renal impairment. Thiazides can add to hyponatremia associated with trimethoprim.
What this interaction means in plain words
Hydrochlorothiazide-lisinopril and Trimethoprim 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.
Hydrochlorothiazide-lisinopril belongs to Cardiovascular; Trimethoprim belongs to Anti Bacterial.
Why it happens
Trimethoprim blocks epithelial sodium channels in the distal nephron, adding to ACE inhibitor-reduced aldosterone effect; additive sodium loss with the thiazide.
What to do
Check serum potassium, sodium and creatinine within several days of starting trimethoprim. Prefer 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?
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Other interactions of Hydrochlorothiazide-lisinopril
- Dofetilide + Hydrochlorothiazide-lisinopril Contraindicated
- Hydrochlorothiazide-lisinopril + Sacubitril / valsartan Contraindicated
- Amifostine + Hydrochlorothiazide-lisinopril Major
- Amiloride + Hydrochlorothiazide-lisinopril Major
- Benazepril + Hydrochlorothiazide-lisinopril Major
- Bendroflumethiazide + Hydrochlorothiazide-lisinopril Major
Other interactions of Trimethoprim
Frequently asked questions
Can I take Hydrochlorothiazide-lisinopril with Trimethoprim?
MediHelp rates the interaction as moderate. Hydrochlorothiazide-lisinopril and Trimethoprim 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. Trimethoprim reduces renal potassium excretion, and with an ACE inhibitor this can lead to significant hyperkalemia, especially in the elderly or those with renal impairment. Thiazides can add to hyponatremia associated with trimethoprim.
How serious is the interaction between Hydrochlorothiazide-lisinopril and Trimethoprim?
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 potassium, sodium and creatinine within several days of starting trimethoprim. Prefer an alternative antibiotic in high-risk patients.
What other medicines interact with Hydrochlorothiazide-lisinopril?
MediHelp also lists interactions of Hydrochlorothiazide-lisinopril with, for example, Dofetilide, Sacubitril / valsartan, Amifostine. The full list is on the Hydrochlorothiazide-lisinopril page.
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