Kaliuretic effect of L-dopa treatment in parkinsonian patients

Hypokalemia, sometimes severe, was observed in some L-dopa-treated parkinsonian patients. The influence of L-dopa on the renal excretion of potassium was studied in 3 patients with hypokalemia and in 5 normokalemic patients by determination of renal plasma flow, glomerular filtration rate, plasma concentration of potassium and sodium as well as urinary excretion of potassium, sodium and aldosterone. L-Dopa intake was found to cause an increased excretion of potassium, and sometimes also of sodium, in the hypokalemic but not in the normokalemic patients. This effect on the renal function could be prohibited by the administration of a peripheral dopa decarbodylase inhibitor. It is not known why this effect occurred in some individuals but not in others, but our results indicate a correlation between aldosterone production and this renal effect of L-dopa.