Spironolactone Prevents Chlorthalidone-Induced Sympathetic Activation and Insulin Resistance in Hypertensive Patients

• Published in: Hypertension (Dallas, Tex. 1979) Vol. 60; no. 2; pp. 319 - 325
• Main Authors: Raheja, Prafull, Price, Angela, Wang, Zhongyun, Arbique, Debbie, Adams-Huet, Beverley, Auchus, Richard J., Vongpatanasin, Wanpen
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD American Heart Association, Inc 01.08.2012; Lippincott Williams & Wilkins
• Subjects: Action Potentials - drug effects; Action Potentials - physiology; Angiotensin II Type 1 Receptor Blockers - pharmacology; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Biphenyl Compounds - pharmacology; Blood and lymphatic vessels; Cardiology. Vascular system; Chlorthalidone - pharmacology; Cross-Over Studies; Diuretics - pharmacology; Drug Therapy, Combination; Experimental diseases; Female; Heart Rate - drug effects; Heart Rate - physiology; Humans; Hypertension - classification; Hypertension - physiopathology; Insulin Resistance - physiology; Male; Medical sciences; Microelectrodes; Middle Aged; Spironolactone - pharmacology; Sympathetic Nervous System - drug effects; Sympathetic Nervous System - physiology; Tetrazoles - pharmacology; Treatment Outcome; Human; Hypertension; Potassium sparing diuretic; Cardiovascular disease; Sympathetic nervous system; Insulin; Aldosterone antagonist; Spironolactone; Sulfonamides; diuretics; Antihypertensive agent; Thiazide; insulin resistance; Chlortalidone
• ISSN: 0194-911X; 1524-4563; 1524-4563
• DOI: 10.1161/HYPERTENSIONAHA.112.194787

Recent studies from our laboratory indicate that chlorthalidone triggers persistent activation of the sympathetic nervous system and promotes insulin resistance in hypertensive patients, independent of serum potassium. Mechanisms underlying these adverse effects of chlorthalidone remain unknown, but increasing evidence in rodents suggests the role of angiotensin and aldosterone excess in inducing both sympathetic overactivity and insulin resistance. Accordingly, we conducted studies in 17 subjects with untreated stage 1 hypertension, measuring sympathetic nerve activity at baseline and after 12 weeks of chlorthalidone alone (25 mg/d), chlorthalidone plus spironolactone, and chlorthalidone plus irbesartan, using randomized crossover design. We found that chlorthalidone alone decreased 24-hour ambulatory blood pressure from 135±3/84±2 to 124±2/78±2 mm Hg and significantly increased sympathetic nerve activity from baseline (from 41±3 versus 49±4 bursts per minute; P<0.01). The addition of spironolactone to chlorthalidone returned sympathetic nerve activity value to baseline (42±3 bursts per minute; P>0.05), whereas the addition of irbesartan failed to alter the sympathetic nerve activity response to chlorthalidone in the same subjects (52±2 bursts per minute; P<0.01) despite a similar reduction in ambulatory blood pressure (121±2/75±2 and 121±2/75±2 mm Hg, respectively). Chlorthalidone alone also increased indices of insulin resistance, which was not observed when used in combination with spironolactone. In conclusion, our study demonstrates beneficial effects of spironolactone in attenuating both chlorthalidone-induced sympathetic activation and insulin resistance in humans, independent of blood pressure reduction. Because sympathetic overactivity and insulin resistance contribute to the poor prognosis in patients with cardiovascular disease, combination therapy of chlorthalidone with mineralocorticoid receptor antagonists may constitute a preferable regimen than chlorthalidone alone in hypertensive patients.