title: Severe Hyponatremia Associated with the Use of Angiotensin II Receptor Blocker/thiazide Combinations.
abstract: There are several widely used combinations of angiotensin II receptor blocker (ARB)/thiazide. The complimentary mechanism of action for such anti-hypertensive therapies is that, while ARB inhibits the vasoconstricting and aldosterone-secreting effects of angiotensin II, hydrochlorothiazide affects the renal tubular mechanisms of electrolyte reabsorption and increases excretion of sodium and chloride in the distal tubule, consequently promoting water excretion. In addition, hypokalemia, which may be triggered by a hydrochlorothiazide-induced increase in urinary potassium loss, is resisted by the use of ARB. Hence, the ARB/thiazide combination is safe in terms of potassium imbalance. For these reasons, fixed-dose ARB/thiazide combination anti-hypertensive drugs have been widely used for the treatment of hypertension. However, there have not been many studies done regarding cases where patients under such regimens showed severe hyponatremia, even when the amount of thiazide included was low. Here we report two cases in which severe hyponatremia occurred following treatment with the ARB/thiazide combinations. Upon discontinuation of the regimen, both patients showed recovery from hyponatremia.
authors.affiliation: Department of Nephrology, KyungHee University School of Medicine, Seoul, Korea.
authors.forename: Da-Rae
authors.initials: DR
authors.lastname: Kim
authors.affiliation: Department of Nephrology, KyungHee University School of Medicine, Seoul, Korea.
authors.forename: Joo-Hee
authors.initials: JH
authors.lastname: Cho
authors.affiliation: Department of Nephrology, KyungHee University School of Medicine, Seoul, Korea.
authors.forename: Won-Seok
authors.initials: WS
authors.lastname: Jang
authors.affiliation: Department of Nephrology, KyungHee University School of Medicine, Seoul, Korea.
authors.forename: Jin-Sug
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Nephrology, KyungHee University School of Medicine, Seoul, Korea.
authors.forename: Kyung-Hwan
authors.initials: KH
authors.lastname: Jeong
authors.affiliation: Department of Nephrology, KyungHee University School of Medicine, Seoul, Korea.
authors.forename: Tae-Won
authors.initials: TW
authors.lastname: Lee
authors.affiliation: Department of Nephrology, KyungHee University School of Medicine, Seoul, Korea.
authors.forename: Chun-Gyoo
authors.initials: CG
authors.lastname: Ihm
keywords: Angiotensin II type 1 receptor blockers; Hydrochlorothiazide; Hyponatremia