Amiloride is a potassium-sparing diuretic.1,2 It is an inhibitor of the epithelial sodium channel (ENaC; K0.5 = 2.6 µM for recombinant δENaC expressed in X. laevis oocytes).3 It inhibits sodium transport from bovine kidney cortex membrane vesicles with an IC50 value of 0.4 µM.4 Amiloride inhibits the urokinase-type plasminogen activator (u-PA; Ki = 7 µM) and cardiac Na+/H+-ATPase (IC50 = 83.8 µM).5,6 It also inhibits calcium currents mediated by transient receptor potential polycystin 3 (TRPP3; IC50 = 143 µM).7 Amiloride (30 mg/kg) reduces mean arterial pressure in spontaneously hypertensive, but not normotensive, rats.8 Formulations containing amiloride have been used alone, and in combination with thiazide diuretics, in the treatment of hypertension.
1.Lingueglia, E., Voilley, N., Lazdunski, M., et al.Physiological society symposium: Ion channels in health and disease. Molecular biology of the amiloride-sensitive epithelial Na+ channelExp. Physiol.81483-492(1996) 2.Qadri, Y.J., Rooj, A.K., and Fuller, C.M.ENaCs and ASICs as therapeutic targetsAm. J. Physiol. Cell Physiol.302(7)C943-C965(2012) 3.Waldmann, R., Champigny, G., Bassilana, F., et al.Molecular cloning and functional expression of a novel amiloride-sensitive Na+ channelJ. Biol. Chem.270(46)27411-27414(1995) 4.Kleyman, T.R., Yulo, T., Ashbaugh, C., et al.Photoaffinity labeling of the epithelial sodium channelJ. Biol. Chem.261(6)2839-2843(1986) 5.Vassalli, J.D., and Belin, D.Amiloride selectively inhibits the urokinase-type plasminogen activatorFEBS Lett.214(1)187-191(1987) 6.Kleyman, T.R., and Cragoe, E.J., Jr.Amiloride and its analogs as tools in the study of ion transportJ. Membr. Biol.105(1)1-21(1988) 7.Dai, X.Q., Ramji, A., Liu, Y., et al.Inhibition of TRPP3 channel by amiloride and analogsMol. Pharmacol.72(6)1576-1585(2007) 8.Barrett, R.J., and Kau, S.T.Myocardial and vascular actions of amiloride in spontaneously hypertensive ratsJ. Pharmacol. Exp. Ther.239(2)365-374(1986)