SEVERE HYPERKALEMIA INDUCED BY TRIMETHOPRIM IN COMBINATION WITH AN ANGIOTENSIN-CONVERTING ENZYME-INHIBITOR IN A PATIENT WITH TRANSPLANTED LUNGS

A 40-year-old woman with transplanted lungs developed life threatening hyperkalaemia (6.8 mmol L(-1)) during high dose treatment with trimet hoprim-sulfamethoxazole for Pneumocystis carinii pneumonia. Trimethopr im has an amiloride-like effect on the distal nephron and may thus ind uce hyperkalaemia, particularly if other contributing factors coexist. The present patient was also treated with the angiotensin-converting enzyme (ACE) inhibitor enalapril, and the combination of ACE-inhibitio n and potassium-sparing diuretics is known to induce hyperkalaemia. Hy perkalaemia was probably induced by the combination of ACE-inhibitor a nd trimethoprim, and this combination may be as dangerous as the combi nation of ACE-inhibitors with other potassium-sparing diuretics.