REVERSIBLE HYPERKALEMIA ASSOCIATED WITH TRIMETHOPRIM-SULFAMETHOXAZOLE

Trimethoprim-sulfamethoxazole (TMP-SMX) is a fixed-dose antimicrobial agent used in a variety of infections, Adverse reactions are more comm on in patients with AIDS, but occasionally occur in immunocompetent pa tients, Renal toxicity is usually a hypersensitivity reaction to the s ulfa component, and manifests as interstitial nephritis or sulfa cryst allization in the renal tubules. Reversible hyperkalemia is a rarely r eported side effect of TMP-SMX therapy attributed to TMP inhibition of potassium secretion in the distal renal tubule in a manner similar to the potassium sparing diuretic, amiloride. In this article, the autho r reports a case of hyperkalemia associated with TMP-SMX occurring in an elderly man with no other risk factors for hyperkalemia, which reso lved upon discontinuation of the drug.