Intended for healthcare professionals

CCBYNC Open access

Rapid response to:

Research

Trimethoprim use for urinary tract infection and risk of adverse outcomes in older patients: cohort study

BMJ 2018; 360 doi: https://doi.org/10.1136/bmj.k341 (Published 09 February 2018) Cite this as: BMJ 2018;360:k341

Rapid Response:

Re: Trimethoprim use for urinary tract infection and risk of adverse outcomes in older patients: cohort study

Thanks for those who have taken the time to respond to our article. We would point readers towards the discussion where we attempt to pragmatically discuss the risks and benefits of trimethoprim against other antibiotics.

Here we carefully discuss Dr Kunal Shah's suggestion that our results are due to the effect of trimethoprim on inhibiting creatinine secretion. Of course we were aware of this, and explain why we feel that this is not the cause of an increase in rate of AKI in those treated with trimethoprim. Even if this were the case, it does not affect the results for hyperkalaemia.

As a nephrologist who treats patients with UTIs and low eGFR I sympathise with Dr Ted Willis. The PHE guidelines do have clear guidance for patients with low eGFR (https://www.gov.uk/government/publications/managing-common-infections-gu...). Trimethoprim may still be an option in patients with no other risk factors for high potassium (such as RAS blockade, K-sparing diuretic use, diabetes with previous hyperkalaemia). Our discussion agrees with Dr Martin Mayfield and Mr Afsin Mahmud (good luck in your exams!) that trimethoprim may still be a useful antibiotic: we have tried hard in this paper to identify patients who are at high-risk of adverse outcomes to enable prescribing clinicians to make informed choices. Overall our results show that trimethoprim is still being prescribed to patients who are at high risk, against existing prescribing guidance (https://www.medicines.org.uk/emc/medicine/24188/SPC/Trimethoprim+Tablets...) as highlighted in Dr Lehman's excellent blog (http://blogs.bmj.com/bmj/2018/02/12/richard-lehmans-journal-reviews-12-f...). We hope that our results will refocus minds on simple measures to avoid harm from this still useful antibiotic.

Laurie Tomlinson

Competing interests: No competing interests

26 February 2018
A Tomlinson Laurie
Associate Professor and Honorary Consultant Nephrologist
LSHTM
Department of Epidemiology and Population Health