Chlorthalidone - a renaissance in use?

Comparison of the Effectiveness and Safety of Chlorthalidone and Hydrochlorothiazide in Patients With Hypertension: A Meta-Analysis

The aim of this study was to compare the effectiveness and safety of chlorthalidone and hydrochlorothiazide in patients with hypertension. The present meta-analysis was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Our search for relevant articles was conducted on PubMed, Scopus, and CINAHIL databases from their inception until March 31, 2023. Keywords used to search for relevant articles included "hydrochlorothiazide," "chlortalidone," "hypertension," "cardiovascular," and "blood pressure." The outcomes assessed in this meta-analysis included changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP). Myocardial infarction, stroke, and all-cause mortality were also assessed. For safety analysis, we evaluated the risk of hypokalemia between the two groups. Any disagreement between the two authors in the data extraction process was resolved through discussion. Eight studies fulfilled the inclusion criteria included in the present meta-analysis. Our analysis showed that chlorthalidone was superior to hydrochlorothiazide in controlling both SBP and DBP, with no significant heterogeneity reported. However, there was no significant difference between the two groups in terms of the risk of myocardial infarction, stroke, all-cause mortality, and hospitalization due to heart failure. The hypokalemia rate was reported to be higher with chlorthalidone compared to hydrochlorothiazide.

Whole blood or plasma: what is the ideal matrix for pharmacokinetic-driven drug candidate selection?

In the present era of drug development, quantification of drug concentrations following pharmacokinetic studies has preferentially been performed using plasma as a matrix rather than whole blood. However, it is critical to realize the difference between measuring drug concentrations in blood versus plasma and the consequences thereof. Pharmacokinetics using plasma data may be misleading if concentrations differ between plasma and red blood cells (RBCs) because of differential binding in blood. In this review, factors modulating the partitioning of drugs into RBCs are discussed and the importance of determining RBC uptake of drugs for drug candidate selection is explored. In summary, the choice of matrix (plasma vs whole blood) is an important consideration to be factored in during drug discovery.

Efficacy of chlorthalidone and hydrochlorothiazide in combination with amiloride in multiple doses on blood pressure in patients with primary hypertension: a protocol for a factorial randomized controlled trial

BACKGROUND

Thiazide diuretics have demonstrated favorable blood pressure lowering efficacy, but the equivalent doses of their more common agents, chlorthalidone and hydrochlorothiazide, are still unclear. Further, concerns exist regarding adverse metabolic effects, which may be attenuated with the concomitant administration of a potassium-sparing diuretic, such as amiloride. This trial aims to investigate the efficacy of chlorthalidone and hydrochlorothiazide, in combination with amiloride at different doses, for initial management of patients with primary hypertension.

METHODS/DESIGN

This is a factorial (2 × 2) randomized double-blinded clinical trial comparing the association of a thiazide diuretic (chlorthalidone 25 mg/day or hydrochlorothiazide 50 mg/day) with a potassium-sparing diuretic (amiloride 10 mg/day or amiloride 20 mg/day) in patients with primary hypertension. The primary outcome will be the mean change from baseline in 24-h systolic and diastolic blood pressure measured by ambulatory blood pressure monitoring. The secondary outcomes will be the mean change from baseline in daytime and nighttime systolic and diastolic blood pressure measured by ambulatory blood pressure monitoring, mean change from baseline in systolic and diastolic blood pressure measured by office blood pressure, incidence of adverse events, variation of laboratory parameters, and proportion of patients who achieved blood pressure control. The follow-up will last 12 weeks. For a P alpha of 0.05, power of 80%, standard deviation of 9 mmHg, and absolute difference of 6 mmHg on systolic blood pressure on 24-h ambulatory blood pressure monitoring, it will be necessary to study a total of 76 patients. The sample size will be increased by 10% to compensate for losses, resulting in 84 patients being randomized.

DISCUSSION

Diuretics are pivotal drugs for the treatment of hypertension. Chlorthalidone and hydrochlorothiazide, in combination with amiloride in multiple doses, will be tested in terms of blood pressure lowering efficacy and safety. Since the intensity of blood pressure reduction is the major determinant of reduction in cardiovascular risk in hypertensive patients, this study will help to determine which combination of diuretics represents the most appropriate treatment for this population.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03928145. Registered on 25 April 2019. Last update on 29 April 2019.

Comparative efficacy and safety of chlorthalidone and hydrochlorothiazide-meta-analysis

Hypertension is a complex syndrome of multiple hemodynamic, neuroendocrine, and metabolic abnormalities. The goals of treatment in hypertension are to optimally control high blood pressure and to reduce associated cardiovascular morbidity and mortality using the most suitable therapy available. Hydrochlorothiazide (HCTZ) and chlorthalidone (CTLD) are with proven hypertensive effects. The topic of our meta-analysis is to compare the efficacy of HCTZ and CTLD therapy in patient with hypertension. A search of electronic databases PubMed, MEDLINE, Scopus, PsyInfo, eLIBRARY.ru was performed. We chose the random-effects method for the analysis and depicted the results as forest plots. Sensitivity analyses were performed in order to evaluate the degree of significance of each study. Of the 1289 identified sources, only nine trials directly compared HCTZ and CTLD and were included in the meta-analysis. Changes in SBP lead to WMD (95% CI) equal to -3.26 mmHg showing a slight but statistically significant prevalence of CTLD. Results from analyzed studies referring to DBP lead to WMD (95% CI) equal to -2.41 mmHg, which is also statistically significant. During our analysis, we found that there were not enough studies presenting enough data on the effect of CTLD and HCTZ on levels of serum potassium and serum sodium. Our meta-analysis has demonstrated a slight superiority for CTLD regarding blood pressure control. At the same time, the two medications do not show significant differences in their safety profile.

Efficacy and Safety of Valsartan or Chlorthalidone vs. Combined Valsartan and Chlorthalidone in Patients With Mild to Moderate Hypertension: The VACLOR Study

Objective:

To evaluate the efficacy and safety of valsartan (V) or chlorthalidone (C) monotherapy in comparison with a fixed combination of valsartan and chlorthalidone (V + C).

Methods:

This 12-week multicenter randomized three-arm open-label study randomly allocated 72 patients to V or C as monotherapy or a combination of V + C. The aim was to measure changes in office systolic blood pressure (SBP) and diastolic blood pressure (DBP) and in 24-hour ambulatory blood pressure monitoring (ABPM) from baseline to week 12, in addition to medication tolerability.

Results:

The proportion of patients achieving target BP in office at week 12 was not statistically different for the three groups. However, comparisons of daytime and nighttime 24-hour ABPM values from baseline to week 12 revealed significant differences in nighttime mean SBP for the three groups, due to a significantly greater reduction in the values in patients assigned to the V + C group (−14.7 vs. −8.7 vs. −10.7, P = .042, V+C; V; C, respectively). Although patients assigned to the V + C group also had greater nighttime reduction in mean DBP values compared with those in the other groups, this difference was not statistically significant. The incidence of adverse events did not differ significantly.

Conclusion:

In patients with hypertension treated with V, C, and both medications combined, the fixed combination of V + C provided a significantly greater reduction of late night to early morning BP values when interventions were assessed with 24-hour ABPM.

Trial registration:

clinicaltrials.gov Identifier: NCT.01850160, https://clinicaltrials.gov/ct2/show/NCT01850160

Chlorthalidone, not hydrochlorothiazide, is the right diuretic for comparison

We have read the study design "Comparison of effects between calcium channel blocker and diuretics in combination with angiotensin II receptor blocker on 24-h central blood pressure and vascular hemodynamic parameters in hypertensive patients: study design for a multicenter, double-blinded, active controlled, phase 4, randomized trial" by Oh GC, et al. with interest. The authors aim to compare the efficacy of amlodipine or hydrochlorothiazide (HCTZ) with an ARB. However, we wish to highlight that chlorthalidone (CTD) is the evidence-based and recommended anti-hypertensive diuretic, and should replace HCTZ in the trial to effectively compare efficacy against the CCB amlodipine.

Evaluation of a Pharmacokinetic Interaction between Telmisartan and Chlorthalidone in Healthy Male Adult Subjects

BACKGROUND AND OBJECTIVE

Combination therapy is recommended for the effective management of hypertension according to most treatment guidelines, including those of the US Joint National Committee. Therefore, pharmacokinetic drug interactions are an important issue in combination therapy for hypertension. In this study, the pharmacokinetic properties of telmisartan and chlorthalidone were evaluated to investigate their pharmacokinetic interactions in healthy subjects.

METHODS

Two separate, randomized, multiple-dose, two-period, one-sequence studies were conducted. In study A, 43 participants received 80 mg of telmisartan orally for 7 days, and were then administered oral chlorthalidone 25 mg for 14 days (days 8-21), coadministered with 80 mg of telmisartan from day 15. In study B, 14 participants received oral chlorthalidone (25 mg) for 13 days, followed by coadministration with 80 mg of telmisartan orally for 7 days.

RESULTS

The geometric mean ratios (GMRs) (90 % confidence intervals [CIs]) of the maximum plasma concentration (C max,ss) and area under the concentration-time curve for the dosing interval at steady state (AUCτ,ss) of telmisartan (with and without chlorthalidone) were 1.018 (0.861-1.203) and 1.099 (1.015-1.190), respectively. For chlorthalidone (with/without telmisartan), the GMRs (90 % CIs) for C max,ss and AUCτ,ss were 0.996 (0.922-1.075) and 0.992 (0.925-1.064), respectively. The GMRs and 90 % CIs for telmisartan and chlorthalidone were all within the 0.80-1.25 range.

CONCLUSION

Thus, in this study, there was no significant pharmacokinetic interaction between telmisartan and chlorthalidone. CLINICALTRIAL.

GOV IDENTIFIER

NCT01806363.

DIURETIC-BASED COMBINATION THERAPY IN PATIENTS WITH ARTERIAL HYPERTENSION: RESULTS OF THE RUSSIAN TRUST STUDY

Arterial hypertension (AH) is one of the most important problems of the modern medicine, due to its exceptionally high prevalence. This study focused on effectiveness and safety of the diuretic-based combination therapy among patients aged >18 years (1476 men and 2989 women) with a clinical diagnosis of Stage 1–3 AH. All patients received fixed-dose combination therapy with atenolol and chlorthalidone. The findings from the TRUST study have confirmed safety and effectiveness of the fixed-dose combination of atenolol and chlorthalidone. 

Which diuretic is the preferred agent for treating essential hypertension: hydrochlorothiazide or chlorthalidone?

Since their introduction over 50 years ago thiazide and thiazide-like diuretics have been a mainstay in the treatment of hypertension. Yet despite outcome evidence with chlorthalidone, the preponderance of usage has been with hydrochlorothiazide-either as monotherapy or in combination with other drugs. There is an increasing debate as to whether or not there are significant differences between hydrochlorothiazide and chlorthalidone. Early outcome studies, upon which the recommendations were made, utilized higher doses than those not only commonly employed in clinical practice, but also studied in more recent outcome trials. In addition, data suggests that chlorthalidone may be more potent, in equal doses, in its BP response than hydrochlorothiazide. A fundamental question asked in the debate is whether or not the benefits attributed to chlorthalidone as a thiazide-like diuretic may be reasonably ascribed to thiazides given differences in their pharmacokinetic properties and perhaps some other more recently noted differences.

Chlorthalidone Reduces Cardiovascular Events Compared With Hydrochlorothiazide

There is significant controversy around whether chlorthalidone (CTD) is superior to hydrochlorothiazide (HCTZ) in hypertension management. The objective of this analysis was to evaluate the effects of CTD compared with HCTZ on cardiovascular event (CVE) rates. We performed a retrospective observational cohort study from the Multiple Risk Factor Intervention Trial data set from the National Heart, Lung, and Blood Institute. The Multiple Risk Factor Intervention Trial was a cardiovascular primary prevention trial where participants were men 35 to 57 years of age enrolled and followed beginning in 1973. CVEs were measured yearly, and time to event was assessed by Cox regression. Systolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, potassium, glucose, and uric acid were measured yearly. The difference between groups was evaluated by repeated-measures mixed modeling, and each model was adjusted for predictors of each variable. CVEs were significantly lower in those on CTD (adjusted hazard ratio: 0.51 [95% CI: 0.43 to 0.61]; P <0.0001) and on HCTZ (adjusted hazard ratio: 0.65 [95% CI: 0.55 to 0.75]; P <0.0001) compared with those who took neither drug. When comparing the 2 drugs, CTD had significantly fewer CVEs compared with HCTZ ( P =0.0016). CTD displayed significantly lower SBP ( P <0.0001), lower total cholesterol ( P <0.0001), lower low-density lipoprotein cholesterol ( P =0.0009), lower potassium ( P =0.0003), and higher uric acid ( P <0.0001) over time compared with HCTZ. In conclusion, both HCTZ and CTD reduce CVEs compared with neither drug. When comparing both drugs, CTD reduces CVEs more than HCTZ, suggesting that CTD may be the preferred thiazide-type diuretic for hypertension in patients at high risk of CVEs.

Impact of new clinical trials on recent guidelines on hypertension management

Guidelines on hypertension diagnosis and treatment have been issued in 2007. Since then, a number of major intervention clinical trials have been designed, carried out, and completed with the aim of investigating unsolved issues related to the impact of the blood pressure-lowering intervention on cardiovascular risk and events. These include, among others, the nephroprotective properties of antihypertensive drugs, the blood pressure targets to be achieved during treatment in uncomplicated and more so in complicated hypertensive patients, the advantages of one drug combination versus another, and the benefits of antihypertensive drugs in the very elderly. All these questions have received a clear-cut answer by the results of recently performed clinical trials, which have been included in the 2009 update document of the European guidelines. This paper will be focused on the 2007 guidelines document and the 2009 update paper, highlighting the new concepts and recommendations provided by the most recent intervention trials.