title: Trimethoprim is a potassium-sparing diuretic like amiloride and causes hyperkalemia in high-risk patients.
abstract: Trimethoprim-sulfamethoxazole is a commonly prescribed antimicrobial agent. Twenty-five years after its introduction into clinical practice, an unrecognized and potentially lethal adverse reaction associated with trimethoprim-sulfamethoxazole therapy, hyperkalemia, was described. Both "high-dose" and "standard-dose" trimethoprim-sulfamethoxazole have been associated with this electrolyte disorder. Recognition of this potassium disturbance led to the subsequent description of the mechanism by which trimethoprim-sulfamethoxazole induced hyperkalemia. Trimethoprim was found to act like the potassium-sparing diuretic amiloride and reduce renal potassium excretion. Hence, trimethoprim is in fact a potassium-sparing diuretic like amiloride and causes hyperkalemia in high-risk patients.
authors.affiliation: Section of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, CT 06520-8029, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Perazella
mesh_terms: D000890:Anti-Infective Agents / Q000009:adverse effects*; D006801:Humans; D006947:Hyperkalemia / Q000139:chemically induced*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000009:adverse effects*
chemical_list: D000890:Anti-Infective Agents; D015662:Trimethoprim, Sulfamethoxazole Drug Combination