Not just chlorthalidone: evidence-based, single tablet, diuretic alternatives to hydrochlorothiazide for hypertension.

Accounting for 15 % of deaths worldwide, hypertension is often treated with hydrochlorothiazide (HCTZ) (50 million prescriptions annually). HCTZ has a <24-h duration of action, is less potent than chlorthalidone and all major antihypertensive drug classes, and is inferior to four antihypertensive drugs for cardiovascular event (CVE) reduction. If there were alternative diuretics, why prescribe HCTZ? Chlorthalidone is often offered as an alternative to HCTZ, but has limited pharmaceutical formulations. However, there are seven evidence-based, single-tablet, alternative diuretics. For reducing CVE, the following are superior to their comparators: chlorthalidone versus four antihypertensives in multiple hypertensive populations; indapamide versus placebo in elderly Chinese (and versus enalapril for left ventricular hypertrophy), triamterene-HCTZ versus placebo in elderly Europeans, amiloride-HCTZ versus three antihypertensives, and indapamide-perindopril versus placebo in three populations. Additionally, chlorthalidone-azilsartan and spironolactone-HCTZ are potent combinations The aldosterone antagonist component of the latter combination has been shown to reduce total mortality by 30 % in heart failure. Five of these seven have multiple dose formulations. Six cost $4-$77 monthly. In conclusion, based on both scientific and practical grounds, new prescriptions for HCTZ are rarely justified.

Should chlorthalidone be the diuretic of choice for antihypertensive therapy?

For decades, diuretic therapy has been a cornerstone in treating hypertension, an approach supported by multiple randomized controlled trials demonstrating reduced morbidity and mortality from cardiovascular events. Yet controversy persists regarding the potential detrimental metabolic effects and side effects of diuretic agents. Within the risk-benefit debates about diuretic therapy is a second dialogue regarding the best thiazide or thiazidelike agent to prescribe. Proponents of chlorthalidone emphasize the demonstrated reductions in cardiovascular events reported from multiple classic trials and its longer half-life, whereas opponents point to its limited availability in low-dose forms and comparable favorable results from hydrochlorothiazide-based therapy to discredit claims of superiority. This review presents the data available on both sides of this issue to help the reader decide which claims are most valid, and offers recommendations for treatment.

Cost-effectiveness of chlorthalidone, amlodipine, and lisinopril as first-step treatment for patients with hypertension: an analysis of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).

OBJECTIVE: To evaluate the cost-effectiveness of first-line treatments for hypertension. BACKGROUND: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) found that first-line treatment with lisinopril or amlodipine was not significantly superior to chlorthalidone in terms of the primary endpoint, so differences in costs may be critical for optimizing decision-making. METHODS: Cost-effectiveness analysis was performed using bootstrap resampling to evaluate uncertainty. RESULTS: Over a patient's lifetime, chlorthalidone was always least expensive (mean $4,802 less than amlodipine, $3,700 less than lisinopril). Amlodipine provided more life-years (LYs) than chlorthalidone in 84% of bootstrap samples (mean 37 days) at an incremental cost-effectiveness ratio of $48,400 per LY gained. Lisinopril provided fewer LYs than chlorthalidone in 55% of bootstrap samples (mean 7-day loss) despite a higher cost. At a threshold of $50,000 per LY gained, amlodipine was preferred in 50%, chlorthalidone in 40%, and lisinopril in 10% of bootstrap samples, but these findings were highly sensitive to the cost of amlodipine and the cost-effectiveness threshold chosen. Incorporating quality of life did not appreciably alter the results. Overall, no reasonable combination of assumptions led to 1 treatment being preferred in over 90% of bootstrap samples. CONCLUSIONS: Initial treatment with chlorthalidone is less expensive than lisinopril or amlodipine, but amlodipine provided a nonsignificantly greater survival benefit and may be a cost-effective alternative. A randomized trial with power to exclude "clinically important" differences in survival will often have inadequate power to determine the most cost-effective treatment.

Thiazide-like diuretics attenuate agonist-induced vasoconstriction by calcium desensitization linked to Rho kinase.

Lowering blood pressure using thiazide-like diuretics, including chlorthalidone and hydrochlorothiazide, has been proven to be effective in clinical studies. However, the mechanisms by which thiazide-like diuretics lower blood pressure are still poorly understood. To evaluate whether thiazide-like diuretics cause calcium desensitization in smooth muscle cells, we measured their effects on agonist-induced increase of blood pressure in Wistar rats in vivo and on agonist-induced vasoconstriction of aortic rings, DNA synthesis, and protein synthesis, RhoA, Rho kinase, and intracellular calcium in vascular smooth muscle cells in vitro. Thiazide-like diuretics significantly attenuated angiotensin II-induced or norepinephrine-induced increase of systolic blood pressure in rats. Thiazide-like diuretics inhibited agonist-induced vasoconstriction of aortic rings in a concentration-dependent manner in the presence and absence of endothelium. The inhibitory effects of thiazide-like diuretics were similar to that of the specific Rho kinase inhibitor Y27632. RT-PCR and immunoblotting showed that RhoA and Rho kinase were significantly reduced in vascular smooth muscle cells after administration of thiazide-like diuretics. In contrast, thiazide-like diuretics did not affect protein tyrosine phosphatase-2 (SHP-2) expression. Agonist-induced changes of intracellular calcium were not affected by thiazide-like diuretics. The study indicates that thiazide-like diuretics inhibit agonist-induced vasoconstriction by calcium desensitization in smooth muscle cells linked to the Rho-Rho kinase pathway.

Major outcomes in high-risk hypertensive patients randomized to angiotensin-converting enzyme inhibitor or calcium channel blocker vs diuretic: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).

CONTEXT: Antihypertensive therapy is well established to reduce hypertension-related morbidity and mortality, but the optimal first-step therapy is unknown. OBJECTIVE: To determine whether treatment with a calcium channel blocker or an angiotensin-converting enzyme inhibitor lowers the incidence of coronary heart disease (CHD) or other cardiovascular disease (CVD) events vs treatment with a diuretic. DESIGN: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), a randomized, double-blind, active-controlled clinical trial conducted from February 1994 through March 2002. SETTING AND PARTICIPANTS: A total of 33 357 participants aged 55 years or older with hypertension and at least 1 other CHD risk factor from 623 North American centers. INTERVENTIONS: Participants were randomly assigned to receive chlorthalidone, 12.5 to 25 mg/d (n = 15 255); amlodipine, 2.5 to 10 mg/d (n = 9048); or lisinopril, 10 to 40 mg/d (n = 9054) for planned follow-up of approximately 4 to 8 years. MAIN OUTCOME MEASURES: The primary outcome was combined fatal CHD or nonfatal myocardial infarction, analyzed by intent-to-treat. Secondary outcomes were all-cause mortality, stroke, combined CHD (primary outcome, coronary revascularization, or angina with hospitalization), and combined CVD (combined CHD, stroke, treated angina without hospitalization, heart failure [HF], and peripheral arterial disease). RESULTS: Mean follow-up was 4.9 years. The primary outcome occurred in 2956 participants, with no difference between treatments. Compared with chlorthalidone (6-year rate, 11.5%), the relative risks (RRs) were 0.98 (95% CI, 0.90-1.07) for amlodipine (6-year rate, 11.3%) and 0.99 (95% CI, 0.91-1.08) for lisinopril (6-year rate, 11.4%). Likewise, all-cause mortality did not differ between groups. Five-year systolic blood pressures were significantly higher in the amlodipine (0.8 mm Hg, P =.03) and lisinopril (2 mm Hg, P<.001) groups compared with chlorthalidone, and 5-year diastolic blood pressure was significantly lower with amlodipine (0.8 mm Hg, P<.001). For amlodipine vs chlorthalidone, secondary outcomes were similar except for a higher 6-year rate of HF with amlodipine (10.2% vs 7.7%; RR, 1.38; 95% CI, 1.25-1.52). For lisinopril vs chlorthalidone, lisinopril had higher 6-year rates of combined CVD (33.3% vs 30.9%; RR, 1.10; 95% CI, 1.05-1.16); stroke (6.3% vs 5.6%; RR, 1.15; 95% CI, 1.02-1.30); and HF (8.7% vs 7.7%; RR, 1.19; 95% CI, 1.07-1.31). CONCLUSION: Thiazide-type diuretics are superior in preventing 1 or more major forms of CVD and are less expensive. They should be preferred for first-step antihypertensive therapy.

An economic evaluation of the JNC hypertension guidelines using data from a randomized controlled trial. Joint National Committee.

BACKGROUND: We wanted to determine the clinical cost of managing hypertension when following the Joint National Committee on Hypertension (JNC) guidelines, including drug therapy, the cost of monitoring for and treating side effects, compliance, and the cost of switching after therapeutic failures. METHODS: The base-case analysis considers antihypertensive agents from four therapeutic classes that were recently evaluated in a large randomized trial: enalapril, amlodipine, acebutolol, and chlorthalidone. Clinical evaluation, therapy, and monitoring for hypertension are modeled with an incidence-based Markov model. Clinical inputs include agent efficacy, side effects, and compliance with dosing schedules. JNC-recommended clinical and laboratory monitoring schedules are followed for each agent. Switches between classes occur for therapeutic failures. Drug and medical care costs are valued in 1995 US dollars. RESULTS: Although patients whose hypertension was initially treated with amlodipine achieved control more readily than patients who were given the other agents, the initial costs to achieve and maintain hypertension control were lowest for chlorthalidone ($641), followed by acebutolol ($920), amlodipine ($946), and enalapril ($948). Maintenance costs were lowest for chlorthalidone. For all agents except chlorthalidone, drug costs were the largest component of overall costs, followed by the costs of office visits, laboratory monitoring, and switching between classes for therapeutic failures. CONCLUSIONS: By following JNC guidelines, a slightly higher percentage of patients will achieve hypertension control with a newer class calcium channel blocker (amlodipine) but at a substantially higher cost than with a generic diuretic (chlorthalidone).