UMEM Educational Pearls

Category: Toxicology

Title: Bactrim + ACE-Inhibitor/ARB + Older Adult = Increased Sudden Death

Keywords: Bactrim, trimethoprim-sulfamethoxazole, ACE-inhibitor, angiotensin receptor blocker, ARB (PubMed Search)

Posted: 11/5/2014 by Bryan Hayes, PharmD (Emailed: 11/13/2014) (Updated: 11/13/2014)
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A new population-based case-control study in older adults has linked the administration of trimethoprim-sulfamethoxazole (Bactrim, TMP-SMX) to increased risk of sudden death in patients also receiving angiotensin converting enzyme inhibitors (ACE-I) or angiotensin receptor blockers (ARB). [1]

Hyperkalemia is the suspected cause. [2] Compared to amoxicillin, TMP-SMX was associated with an increased risk of sudden death (adjusted odds ratio 1.38, 95% confidence interval 1.09 to 1.76) within 7 days of exposure to the antibiotic.

Practice Change

In older patients receiving ACE-Is or ARBs, TMP-SMX is associated with an increased risk of sudden death. When appropriate, alternative antibiotics should be considered.


  1. Fralick M, et al. Co-trimoxazole and sudden death in patients receiving inhibitors of renin-angiotensin system: population-based study. BMJ 2014;349:g6196. [Free open access link]
  2. Antoniou T, et al. Trimethoprim-sulfamethoxazole-induced hyperkalemia in patients receiving inhibitors of the renin-angiotensin system: a population-based study. Arch Intern Med 2010;170(12):1045-9. [PMID 20585070]

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