Abstract: A diuretically active combination comprising furosemide and triamterene in a ratio of 1:1 to 1:2, in which furosemide is in the form of controlled release so as to facilitate solubilization of the furosemide in triamterene micelles to stabilize the combination as mixed micelles of low polydispersity yielding dissolution rates in in vitro tests of furosemide of not more than about 1.5% after about one hour at pH 1.5 to 3.5 and a slow release of not more than about 4.5% at pH 5.5 concurrent with a release of triamterene of about 60-70% and 80%, respectively, and with a release of not more than 85% furosemide after eight hours at pH 7.5 in salt solutions of adjusted pH.