Telmisartan is an angiotensin II receptor antagonist and chlorthalidone is a thiazide-like diuretics. In this study, we report serious adverse events (SAEs) during clinical trial for pharmacokinetic interaction between telmisartan and chlorthalidone in healthy Korean subjects. Two separate, randomized, multiple-dose, two-period, one-sequence studies were conducted at Kyungpook National University Hospital. In part A, 43 volunteers received telmisartan for 7 days, and then chlorthalidone for 14 days (days 8-21). Telmisartan was co-administered during day 15-21 to evaluate the effects of chlorthalidone on the pharmacokinetics of telmisartan at steady state. A healthy 36-year-old male in part A was referred to the emergency room due to severe nausea and vomiting developed about 3 h after administration of chlorthalidone on day 9. Hypokalemia and QT prolongation were observed during his initial laboratory examination and electrocardiogram (ECG) monitoring in the emergency unit. Nausea and vomiting improved after conservative management with hospitalization for 9 days. We consider that the episodes of excessive nausea and vomiting resulted in hypokalemic state which was potentiated by chlorthalidone. And the hypokalemic state caused the lengthening of the QT interval on ECG.
Adult ; Arrhythmias, Cardiac ; Chlorthalidone* ; Diuretics ; Electrocardiography ; Emergency Service, Hospital ; Gyeongsangbuk-do ; Hospitalization ; Humans ; Hypokalemia ; Male ; Nausea ; Pharmacokinetics ; Receptors, Angiotensin ; Volunteers ; Vomiting

PURPOSE: Thiazide diuretics exert their hypotensive efficacy through a combined vasodilator and diuretic effect. The present study was conducted to assess the inhibitory effect of thiazide diuretic, hydrochlorothiazide, and the thiazide-like diuretics, indapamide and chlorthalidone on contractile responses to norepinephrine and arginine vasopressin in aortic rings from 2K1C renal hypertensive and sham-clipped normotensive rats. METHODS: 2K1C hypertension was made by clipping the left renal artery and age-matched control rats received a sham treatment. Changes in the tension of aortic ring preparations were measured isometrically. RESULTS: Indapamide inhibits the contractile responses to norepinephrine and vasopressin in aortic rings from 2K1C rats, while it did not modify in control rats. The inhibitory effect of indapamide was abolished by endothelium removal. Hydrochlorothiazide or chlorthalidone did not affect the vasoconstriction induced by norepinephrine and vasopressin either in sham or in 2K1C hypertensive rats. CONCLUSION: These results suggest that indapamide inhibits the contractile responses to norepinephrine and vasopressin via an endothelium-dependent mechanism in 2K1C renal hypertension.
Animals ; Aorta ; Arginine Vasopressin ; Chlorthalidone ; Diuretics ; Endothelium ; Hydrochlorothiazide ; Hypertension ; Hypertension, Renal ; Indapamide ; Norepinephrine ; Placebos ; Rats ; Renal Artery ; Salicylamides ; Sodium Chloride Symporter Inhibitors ; Vasoconstriction ; Vasodilation ; Vasopressins