NSTK · 01.2026Independent supplement reference
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Edition 1.0Updated August 1, 2026

Supplement × Prescription·Evidence index

Potassium and Trimethoprim-Sulfamethoxazole: what the published research says

PubMed indexes 8 records that name Potassium and Trimethoprim-Sulfamethoxazole together, either in the title or in an interaction, co-administration, or pharmacokinetic context. Each one is listed below with its study design and, where the abstract states one, the authors’ own conclusion, quoted and linked. This page reports that literature. It does not tell you whether to combine them.

Read this first

An evidence index, not guidance.

Every statement below is attributed to a named, dated, linked source.

This page lists published research relevant to Potassium and Trimethoprim-Sulfamethoxazole. It deliberately does not state whether the combination is safe, whether it interacts, in which direction, at what dose, or how far apart to take them.

The research

8 studies naming Potassium and Trimethoprim-Sulfamethoxazole.

Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.

Co-trimoxazole induced hyperkalemia and potassium monitoring in hospitalized patients.

International journal of clinical pharmacy · 2020 · PMID 33025449

Comparative StudyHuman subjects30 participants

“Conclusion Adherence to Dutch guidelines was poor as serum potassium monitoring was often not performed. As intravenous co-trimoxazole usage is associated with a significant increase in mean serum potassium, monitoring is strongly recommended.”

Plantaz et al. · From the abstract

Names both Potassium and Trimethoprim-Sulfamethoxazole in its title.

The effect of co-trimoxazole on serum potassium concentration: safety evaluation of a randomized controlled trial.

British journal of clinical pharmacology · 2017 · PMID 28192629

Multicenter StudyRandomized Controlled Trial

“Co-trimoxazole significantly increases serum potassium concentration, even in participants not using antikaliuretic drugs. While the magnitude of increase was often minor, a small proportion in our outpatient cohort developed hyperkalaemia of clinical importance.”

Chan et al. · Authors' conclusion

Names both Potassium and Trimethoprim-Sulfamethoxazole in its title.

Impact of trimethoprim on serum creatinine, sodium, and potassium concentrations in patients taking trimethoprim-sulfamethoxazole without changes in glomerular filtration rate.

Journal of clinical pharmacy and therapeutics · 2022 · PMID 35545234

Human subjects

“This study is the first report to demonstrate the degree of changes in SCr, Na+ , and K+ concentrations after initiation of TMP-SMX treatment. If SCr is elevated after initiation of TMP-SMX treatment, clinicians should be aware of decreased Na+ and increased K+ concentrations. TMP may increase the risks of hyponatremia and hyperkalemia in a dose-dependent manner without altering GFR.”

Yokoyama et al. · Authors' conclusion

Names both Potassium and Trimethoprim-Sulfamethoxazole in its title.

Co-trimoxazole induced hyperkalemia and potassium monitoring in hospitalized patients.

International journal of clinical pharmacy · 2020 · PMID 32390087

Human subjects30 participants

“Conclusion Adherence to Dutch guidelines was poor as serum potassium monitoring was often not performed. As intravenous co-trimoxazole usage is associated with a significant increase in mean serum potassium, monitoring is strongly recommended.”

Plantaz et al. · From the abstract

Names both Potassium and Trimethoprim-Sulfamethoxazole in its title.

Effect of standard-dose trimethoprim/sulfamethoxazole on the serum potassium concentration in elderly men.

The Annals of pharmacotherapy · 1996 · PMID 8729886

Human subjects

“Therapy with standard-dose TMP/SMX is associated with a slight increase in the serum potassium concentration. Routine monitoring of the serum potassium concentration in patients who are treated with standard-dose TMP/SMX therapy is unnecessary. However, TMP/SMX should be considered as a possible cause of unexplained hyperkalemia in elderly patients receiving TMP/SMX therapy.”

Witt et al. · Authors' conclusion

Names both Potassium and Trimethoprim-Sulfamethoxazole in its title.

Severe hyponatremia due to trimethoprim-sulfamethoxazole: a case report.

AME case reports · 2025 · PMID 40330924

Case Reports

“Timely identification and careful monitoring of TMP-SMX-induced hyponatremia enabled the correction of sodium levels without severe complications. Thus, this report underscores the importance of vigilant monitoring and prompt identification of hyponatremia in patients undergoing TMP-SMX treatment. Further research is warranted due to limited data on the precise mechanisms of TMP-SMX-induced hyponatremia.”

Alrasheed et al. · Authors' conclusion

Names Potassium and Trimethoprim-Sulfamethoxazole together in an interaction, co-administration, or pharmacokinetic context.

Limitations

What this evidence cannot tell you.

Search-based evidence indexes have real limits, and it is worth being explicit about them:

NutriStack

Track what you actually take.

NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers Potassium, Trimethoprim-Sulfamethoxazole, and several hundred other substances.

The checker is a research and organisation tool, not a clinical decision aid, and its per-pair assessments are excluded from search until they pass claim-level review.

NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.