Trimethoprim-Sulfamethoxazole Use in Patients with Acute Kidney Injury

Contraindications and Risks

The American College of Nephrology recommends that TMP-SMX should be avoided in patients with severe renal insufficiency (creatinine clearance <15 ml/min) and used with extreme caution in patients with acute kidney injury due to increased risk of further kidney damage and drug accumulation 1, 2
Each nephrotoxic medication administration presents 53% greater odds of developing AKI, and this risk compounds when patients receive multiple nephrotoxins 3

TMP-SMX can cause AKI through multiple mechanisms, including direct tubular toxicity 2
Hyperkalemia (due to trimethoprim's potassium-sparing effects) is a potential mechanism of kidney injury 3

If TMP-SMX must be used in patients with AKI, consider the severity and cause of AKI before initiating therapy, and evaluate whether a less nephrotoxic alternative antibiotic is available 3, 4
For creatinine clearance <15 ml/min, TMP-SMX is not recommended 1, 2
Monitor renal function closely during treatment, and be vigilant for signs of worsening renal function and discontinue if AKI worsens 4

When possible, consider alternative antibiotics with less nephrotoxic potential in patients with AKI, such as fluoroquinolones (ofloxacin, ciprofloxacin) or β-lactam antibiotics 3, 5