Losartan and Sulfamethoxazole Trimethoprim: Drug Interaction Guide

Quick answer: This combination requires caution. Losartan and Sulfamethoxazole Trimethoprim can be used together with adjustments and monitoring.

Interaction severity: Moderate — caution required

How Losartan interacts with Sulfamethoxazole Trimethoprim

Trimethoprim acts like a potassium-sparing diuretic by blocking epithelial sodium channels in the distal nephron. Combined with losartan, this increases the risk of hyperkalaemia.

What you should do

Check baseline renal function and potassium, then recheck during therapy in higher-risk patients. Consider an alternative antibiotic if hyperkalaemia risk is high.

Key facts

Severity

Moderate — caution required

Mechanism

Trimethoprim acts like a potassium-sparing diuretic by blocking epithelial sodium channels in the distal nephron. Combin...

Action

Check baseline renal function and potassium, then recheck during therapy in higher-risk patients. Consider an alternativ...

Important medical disclaimer: This page provides educational information about drug interactions for general reference. It is not a substitute for professional medical advice, diagnosis, or treatment. Always discuss your specific medications with a qualified healthcare provider before starting, stopping, or changing any treatment. About our editorial team.

Frequently asked questions

Can I take Losartan and Sulfamethoxazole Trimethoprim together?

With caution. Check baseline renal function and potassium, then recheck during therapy in higher-risk patients. Consider an alternative antibiotic if hyperkalaemia risk is high.

What is the severity of this interaction?

The interaction between Losartan and Sulfamethoxazole Trimethoprim is classified as Moderate — caution required. Trimethoprim acts like a potassium-sparing diuretic by blocking epithelial sodium channels in the distal nephron. Combined with losartan, this increases the risk of hyperkalaemia.

What should I do if I'm prescribed both?

Check baseline renal function and potassium, then recheck during therapy in higher-risk patients. Consider an alternative antibiotic if hyperkalaemia risk is high. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

Last reviewed: by iMedic Medical Editorial Team. Our editorial process.