Structural bases for Na+-Cl- cotransporter inhibition by thiazide diuretic drugs and activation by kinases.

The Na+-Cl- cotransporter (NCC) drives salt reabsorption in the kidney and plays a decisive role in balancing electrolytes and blood pressure. Thiazide and thiazide-like diuretics inhibit NCC-mediated renal salt retention and have been cornerstones for treating hypertension and edema since the 1950s. Here we determine NCC co-structures individually complexed with the thiazide drug hydrochlorothiazide, and two thiazide-like drugs chlorthalidone and indapamide, revealing that they fit into an orthosteric site and occlude the NCC ion translocation pathway. Aberrant NCC activation by the WNKs-SPAK kinase cascade underlies Familial Hyperkalemic Hypertension, but it remains unknown whether/how phosphorylation transforms the NCC structure to accelerate ion translocation. We show that an intracellular amino-terminal motif of NCC, once phosphorylated, associates with the carboxyl-terminal domain, and together, they interact with the transmembrane domain. These interactions suggest a phosphorylation-dependent allosteric network that directly influences NCC ion translocation.

Knowing the minimal detectable dose can facilitate the interpretation of a hair test result: Case example with chlortalidone.

In case of an adverse analytical finding, a low (estimate) urine concentration can be the consequence of 2 very different situations: it can be the tail end of a drug voluntarily consumed to enhance athletic performance, even by microdosing (which is not effective for all drugs), or it can be the result of a contamination, irrespective of its source. For numerous doping agents, a hair test can allow discriminating doping from contamination based on the measured concentration or even the absence of the target drug. Given hair produces incremental concentrations, its analysis offers the possibility of establishing a pattern of drug use and thus, verifying self-reported histories of exposure. In order to provide a retrospective calendar of drug use, segmental analysis of the hair strand can be performed. In doping, the usual practice is to test the substance in short segments, such as 1 cm to avoid drug dilution when using larger segments. During the last months, seven athletes have returned an adverse analytical finding for the diuretic chlortalidone, with reported urine concentrations in the range 20 to 50 ng/mL. All these athletes submitted, via their legal team, their hair for establishing a pattern of exposure. Results were always consistent with incidental contamination (hair concentration lower than 5 pg/mg), although the source of contamination was never identified. The interpretation of the findings was established in the light of the limited literature, including hair tests after microdosing and therapeutic use.

Preferred diuretic therapy for primary hypertension: Chlorthalidone or hydrochlorothiazide?

ABSTRACT: Because of its greater reduction of major adverse cardiovascular events (MACE), chlorthalidone is recommended over hydrochlorothiazide as the preferred diuretic for patients with primary hypertension. However, hydrochlorothiazide is more commonly prescribed than chlorthalidone for this condition. This article reviews recent studies investigating the effectiveness of chlorthalidone and hydrochlorothiazide in reducing MACE, to help clinicians make an evidence-based informed decision on which diuretic to prescribe.

Diuretics use in the management of hypertension.

Diuretics have been used for decades in the treatment of hypertension. Its efficacy has been demonstrated in numerous clinical trials. It is well known that the reduction in cardiovascular risk is a consequence of the reduction in blood pressure levels regardless of the drug used, but thiazide diuretics continue to be first-line drugs, especially in low doses and combined with other drugs. The debate on the advantages of using chlorthalidone or hydrochlorothiazide continues, however hydrochlorothiazide is drug most used and for which there is greater availability. The association with potassium-sparing diuretics increases the effectiveness and reduces the adverse reactions of thiazides. A new group of drugs, close to potassium-sparing diuretics, that antagonise aldosterone synthase are showing promising results as antihypertensives. There are no significant differences between men and women regarding the antihypertensive effect of thiazide diuretics.

Chlorthalidone vs Hydrochlorothiazide for Hypertension Treatment After Myocardial Infarction or Stroke: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Patients with prior myocardial infarction (MI) or stroke have a greater risk of recurrent cardiovascular (CV) events. Objective: To evaluate the association of chlorthalidone (CTD) vs hydrochlorothiazide (HCTZ) with CV outcomes and noncancer deaths in participants with and without prior MI or stroke. Design, Setting, and Participants: This was a prespecified secondary analysis of the Diuretic Comparison Project (DCP), a pragmatic randomized clinical trial conducted within 72 participating Veterans Affairs health care systems from June 2016 to June 2021, in which patients aged 65 years or older with hypertension taking HCTZ at baseline were randomized to continue HCTZ or switch to CTD at pharmacologically comparable doses. This secondary analysis was performed from January 3, 2023, to February 29, 2024. Exposures: Pharmacologically comparable daily dose of HCTZ or CTD and history of MI or stroke. Main Outcomes and Measures: Outcome ascertainment was performed from randomization to the end of the study. The primary outcome consisted of a composite of stroke, MI, urgent coronary revascularization because of unstable angina, acute heart failure hospitalization, or noncancer death. Additional outcomes included achieved blood pressure and hypokalemia (potassium level <3.1 mEq/L; to convert to mmol/L, multiply by 1.0). Results: The DCP randomized 13 523 participants to CTD or HCTZ, with a mean (SD) study duration of 2.4 (1.4) years. At baseline, median age was 72 years (IQR, 69-75 years), and 96.8% were male. Treatment effect was evaluated in subgroups of participants with (n = 1455) and without (n = 12 068) prior MI or stroke at baseline. There was a significant adjusted interaction between treatment group and history of MI or stroke. Participants with prior MI or stroke randomized to CTD had a lower risk of the primary outcome than those receiving HCTZ (105 of 733 [14.3%] vs 140 of 722 [19.4%]; hazard ratio [HR], 0.73; 95% CI, 0.57-0.94; P = .01) compared with participants without prior MI or stroke, among whom incidence of the primary outcome was slightly higher in the CTD arm compared with the HCTZ arm (597 of 6023 [9.9%] vs 535 of 6045 [8.9%]; HR, 1.12; 95% CI, 1.00-1.26; P = .054) (P = .01 for interaction). The incidence of a nadir potassium level less than 3.1 mEq/L and hospitalization for hypokalemia differed among those with and without prior MI or stroke when comparing those randomized to CTD vs HCTZ, with a difference only among those without prior MI or stroke (potassium level <3.1 mEq/L: prior MI or stroke, 43 of 733 [5.9%] vs 37 of 722 [5.1%] [P = .57]; no prior MI or stroke, 292 of 6023 [4.9%] vs 206 of 6045 [3.4%] [P < .001]; hospitalization for hypokalemia: prior MI or stroke, 14 of 733 [1.9%] vs 16 of 722 [2.2%] [P = .72]; no prior MI or stroke: 84 of 6023 [1.4%] vs 57 of 6045 [0.9%] [P = .02]). Conclusions and Relevance: Results of this secondary analysis of the DCP trial suggest that CTD may be associated with reduced major adverse CV events and noncancer deaths in patients with prior MI or stroke compared with HCTZ. Trial Registration: ClinicalTrials.gov Identifier: NCT02185417.

Effect of antihypertensive agents on sleep apnea and ambulatory blood pressure in patients with hypertension: A randomized controlled trial.

BACKGROUND: Obstructive sleep apnea (OSA) and hypertension are common conditions that may be linked through sympathetic activation and water retention. We hypothesized that diuretics, which reduce the body water content, may be more effective than amlodipine, a blood pressure (BP)-lowering agent implicated with edema, in controlling OSA in patients with hypertension. We also aimed to compare the effects of these treatments on ambulatory blood pressure monitoring (ABPM). METHODS: In a randomized, double-blind clinical trial, we compared the effects of chlorthalidone/amiloride 25/5 mg with amlodipine 10 mg on OSA measured by portable sleep monitor and BP measured by ABPM. The study included participants older than 40 who had moderate OSA (10-40 apneas/hour of sleep) and BP within the systolic range of 140-159 mmHg or diastolic range of 90-99 mmHg. RESULTS: The individuals in the experimental groups were comparable in age, gender, and other relevant characteristics. Neither the combination of diuretics nor amlodipine alone reduced the AHI after 8 weeks of treatment (AHI 26.3 with diuretics and 25.0 with amlodipine. P = 0.713). Both treatments significantly lowered office, 24-h, and nighttime ABP, but the two groups had no significant difference. CONCLUSION: Chlorthalidone associated with amiloride and amlodipine are ineffective in decreasing the frequency of sleep apnea episodes in patients with moderate OSA and hypertension. Both treatments have comparable effects in lowering both office and ambulatory blood pressure. The notion that treatments could offer benefits for both OSA and hypertension remains to be demonstrated. TRIAL REGISTRATION CLINICALTRIALS. GOV IDENTIFIER: NCT01896661.

A design of experiment based RP-HPLC method for the simultaneous estimation of antihypertensive drugs with greenness assessment.

The correlation between blood pressure (BP) and cardiovascular risk has a continuous, positive, and linear pattern. Lowering high BP decreases the risk associated with cardiovascular disease. Chlorthalidone (CHD) and Losartan potassium (LOS) combination is used to treat hypertension. The analytical community was concerned with minimizing or reducing the use of toxic chemicals and solvents. Therefore, the current study aimed to develop a rapid, sensitive, and cost-effective green RP-HPLC method to determine CHD and LOS simultaneously in a short analysis of time. Method optimization was performed by Central composite design (CCD), the flow rate and the change of time were chosen as factors. Effective separation was conducted on Zorbax SB-C18 (4.6 mm × 150 mm, 5 µm) column by gradient mobile phase comprising phosphate buffer and ethanol flowing at 0.859 ml/min, and the wavelength detected at 230 nm. As per ICH criteria, the technique was proven to be precise, accurate, and linear over the concentration range of 4.3-8.1 µg/ml for CHD and 35-65 µg/ml for LOS. Furthermore, the method's greenness was examined by three different metrics, confirming that less toxic effect on the environment. Hence, the optimized approach proves to be eco-friendly, simple, and robust for the concurrent evaluation of CHD and LOS in pharmaceutical formulations.

Clortalidona para adultos com hipertensão arterial sistêmica com controle inadequado da pressão arterial / Chlorthalidone for adults with systemic arterial hypertension with inadequate blood pressure control

INTRODUÇÃO: A hipertensão arterial sistêmica (HAS), uma doença crônica, é um grave problema de saúde pública, caracterizada por níveis elevados e persistentes da pressão sanguínea, medidos em geral como uma razão da pressão arterial sistólica e diastólica (respectivamente maior ou igual a 140 mmHg; e/ou maior ou igual a 90 mmHg). Esta é uma doença altamente prevalente em todo o mundo. No Brasil, os números podem variar de acordo com a metodologia utilizada. Reportou-se na Pesquisa Nacional de Saúde de 2013, cujos dados são obtidos por autorrelato, a prevalência de hipertensão em 21% dos pacientes, mas ao considerar a aferição da pressão arterial e uso de medicamentos, o percentual de adultos com pressão arterial ≥140/90 mmHg foi de 32%. Sabe-se que a falta de controle da pressão arterial pode elevar o risco de ocorrência de eventos cardiovasculares, como infarto agudo do miocárdio, insuficiência cardíaca, acidente vascular cerebral, doenças renais, entre outros. Isso consequentemente pode causar problemas crônicos que reduzem a qualidade de vida do indivídu

Podcast POEMs (BVS APS): HCTZ x Clortalidona na prevenção de DCV: Quem ganha? Em epidemiologia: Desfechos compostos

Olá! Eu sou o Luciano Duro, médico de família e comunidade, mestre e doutor em epidemiologia e neste sétimo episódio da terceira temporada, vou falar sobre um estudo publicado em dezembro de 2022 no New England Journal of Medicine, comparando a hidroclorotiazida com a clortalidona na prevenção de eventos indesejáveis, principalmente cardiovasculares. Junto à discussão sobre este artigo, vou falar em epidemiologia, sobre desfechos compostos, uma forma de se organizar os desfechos a serem estudados em ensaios clínicos.

Chlorthalidone vs Hydrochlorothiazide for Hypertension-CV Events: Did the Design Influence the Outcome?

The Diuretic Comparison Project (DCP)1 was a real world study planned to evaluate in a pragmatic manner whether Chlorthalidone (CTD), as compared with Hydrochlorothiazide (HCTZ), would reduce the risk of major nonfatal cardiovascular disease outcomes in elderly hypertensive participants (≥65 years) who were receiving HCTZ (25 or 50 mg) at baseline. This study being a real world study lacks the robustness of a randomized controlled trial. The principle limitation being unequal exposure of the two diuretics, prolonged unknown duration of exposure to HCTZ vs a short exposure to CTD (Median 2.4 years). In the high risk population with history of MI/Stroke, CTD conferred a lower risk of primary outcome as compared to low risk population where no significant difference in outcome was seen in both diuretics. Other factors included, lack of established dose equivalency of the two diuretics and absence of use of 12.5 mg HCTZ in older hypertensives. How to cite this article: Pareek A, Messerli FH, Ram CVS. Chlorthalidone vs Hydrochlorothiazide for Hypertension-CV Events: Did the Design Influence the Outcome? J Assoc Physicians India 2023;71(10):93-93.

Resúmenes: Clortalidona para tratar la hipertensión del paciente con enfermedad renal crónica avanzada / Abstracts: Chlorthalidone for treating hypertension in patients with advanced chronic kidney disease

No disponible

Avaliação da qualidade de medicamentos contendo clortalidona / Quality Assessment of medication containing chlorthalidone

Os diuréticos são a classe de fármacos mais utilizados no tratamento da hipertensão devido a sua eficácia terapêutica e ao baixo custo. Isto faz com que uma grande variedade de medicamentos esteja disponível no comercio e atrelado a este fator muitas empresas tem seus lotes de medicamentos suspensos devido a desvios de qualidade e das modificações realizadas nas formulações após o seu registro. A clortalidona é um diurético tiazídico indicada para o tratamento de hipertensão arterial leve ou moderada e com normalidade das funções cardíacas e renal. Este trabalho teve como objetivo verificar a qualidade de comprimidos de clortalidona comercializados no município de Sinop/ MT. O controle de qualidade foi realizado como estabelecido na Farmacopeia Brasileira quinta edição (ensaios de identificação, pureza, doseamento, ensaios referentes a forma farmacêutica de comprimidos e perfil de dissolução), de cinco produtos contendo clortalidona 25 mg sendo um produto de medicamento referência, dois de medicamentos genéricos e dois de medicamentos similares. Verificou-se que todos os produtos foram aprovados, cumprindo com todos os requisitos exigidos nos ensaios de qualidade e que estudos referentes ao perfil de dissolução nos lotes de produção de medicamentos são importantes para prever a absorção adequada do princípio ativo

Diuretics are the most used class of drugs that are used to treat hypertension because of their therapeutic efficiency and low cost. This makes a wide variety of medicines commercially available and, linked to this factor, many companies have their batches of medicines suspended due to deviations of quality and modifications made in the formulas after their registration. Chlorthalidone, is a thiazide diuretic drug indicated for treatment of hypertension of patients with mild or moderate hypertension, and with normal cardiac and renal function. This work aimed to assess and compare the quality of medicines containing chlorthalidone commercialized in Sinop-MT. The quality control was performed as established in the fifth edition of the Brazilian Pharmacopoeia (identification, purity and dosage assays, tests referring to the pharmaceutical form of the tablets and their dissolution profile). Among five products containing 25 mg of chlortalidone, one was a reference drug product, two were generic and two were similar drugs. It was found that all products were approved, meeting all the requirements required in the quality tests, and that studies concerning the dissolution profile in batches of drug production are important to predict adequate absorption of the active principle

Serious adverse events during clinical trial for pharmacokinetic interaction between telmisartan and chlorthalidone in healthy Korean subjects: A case report

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.

O uso de diuréticos tiazídicos no tratamento HAS reduzem os eventos cardiovasculares? Há diferença de eficácia entre a hidroclortiazida e clortalidona?

Sobre o uso de diuréticos tiazídicos no tratamento de HAS, grandes ensaios mostram redução de eventos cardiovasculares somente com clortalidona. A dúvida é: existe algum trabalho que mostre que a hidroclortiazida (HCTZ), com ajuste de posologia, tenha a mesma eficácia? E a clortalidona tem duração de efeito de 24 horas, enquanto a HCTZ de 12 horas?
Realmente clortalidona foi a droga mais testada nos grandes ensaios clínicos, entre os diuréticos. Nesse contexto, ALLHAT é, provavelmente, o mais emblemático ensaio clínico, visto que tentou definir qual a melhor primeira droga para manejo da HAS (e usou clortalidona como diurético).
Há poucos estudos comparando diretamente os dois fármacos, e a maioria deles compara desfechos intermediários como redução da pressão arterial ou da hipertrofia ventricular (2,3), sempre com vantagem para a clortalidona. Entretanto, recente estudo de coorte retrospectivo mostrou redução de eventos cardiovasculares com o uso de clortalidona comparado com hidroclorotiazida (4). Há outro estudo bem interessante nesse contexto, cujo desenho permitia a escolha de HCTZ ou clortatlidona como escolha para tratamento da HAS. No meio do estudo foi decidido que só seria utilizado clortalidona pela diminuição consistente de desfechos clínicos quando comparado com HCTZ (5). Por isso, realmente há evidências sugerindo que clortalidona é melhor que HCTZ para desfechos intermediários ou primordiais.
Sobre a posologia, há interessante artigo tentando justificar sob o ponto de vista farmacodinâmico e farmacocinético a vantagem da clortalidona sobre a HCTZ. Realmente para uma dose única a HCTZ tem duração de 12 horas. Contudo, para uso continuado, sua duração é de 16 a 24 horas. Já no caso da clortalidona, uma única dose dura de 24 a 48 horas, e o uso continuado de 48 a 72 horas. Visto isso, não há necessidade de utilizar nenhuma das duas medicações mais de uma vez ao dia. Esse mesmo artigo discute a dose-resposta da HCTZ, que tem crescimento linear até 25mg/dia em dose única, e depois não há ganho na diminuição da pressão com aumento da dose (mas há consequente aumento da hipocalemia, o que aumenta mortalidade). Por isso, não há motivo para usar HCTZ em doses superiores a 25 mg/dia para tratamento da HAS (outras situações como Doença De Meniere tem o uso de doses maiores justificado) (6).
Sugiro também leitura de um outro artigo que discute porque, mesmo com tantas provas de maior efetividade da clortalidona, nos Estados Unidos ainda HCTZ é o diurético mais utilizado (7). Recente diretriz do NICE sobre tratamento anti-hipertensivo desestimula o uso do HCTZ, e diz que, no caso de uso de diurético, clortalidona deve ser a medicação de eleição (8).

Segunda Opinião Formativa: O uso de diuréticos tiazídicos no tratamento da hipertensão arterial sistêmica reduz os eventos cardiovasculares? Há diferença de eficácia entre a hidroclortiazida e clortalidona?

Resposta sistematizada, com base em revisão bibliográfica, sobre o uso de diuréticos tiazídicos no tratamento a hipertensão arterial sistêmica (HAS) e sobre diferenças de eficácia entre a hidroclortiazida e clortalidona. O texto reúne também informações sobre definição, sintomas, diagnóstico, manejo e tratamento da HAS.

Existem diferenças entre os diversos diuréticos? / Are there differences among the several diuretics?

Esse artigo faz uma breve revisão sobre as principais classes dos diuréticos e suas indicações. Aborda com detalhes os diuréticos tiazídicos, principal classe utilizada no tratamento da hipertensão arterial, abordando as diferenças entre eles em relação à estrutura, farmacodinâmica e farmacocinética. Posteriormente, avalia criteriosamente os principais trials clínicos, discutindo os efeitos dos tiazídicos na redução da pressão arterial, nos eventos cardiovasculares, incluindo acidente vascular encefálico, insuficiência cardíaca congestiva e doença arterial coronariana; além de abordar os efeitos sobre a glicemia. Finalmente, compara os principais diuréticos tiazídicos em relação à potência e efetividade na redução da pressão arterial.

This article is a brief review on the main classes of diuretics and indications. It discusses in detail the thiazide diuretics, the principal class used in the treatment of hypertension, addressing the differences between them in relation to structure, pharmacokinetics and pharmacodynamics. Afterwards, carefully assesses the key clinical trials, discussing the effects of thiazides in reducing blood pressure, cardiovascular events, including stroke, heart failure and coronary artery disease; in addition to addressing the effects on blood glucose. Finally, it compares the main thiazide diuretics in relation to the potency and effectiveness in lowering blood pressure.

Diferencias y similitudes entre diuréticos / Differences and similarities among diuretics

Los diuréticos tiazídicos son los fármacos más recomendados para el tratamiento inicial de la hipertensión arterial, por su bajo coste, pero también por su eficacia y tolerabilidad tanto en monoterapia como en combinación. Aunque el fármaco más utilizado es la hidroclorotiazida existen argumentos a favor de su sustitución por clortalidona. El uso de tiazidas reduce la incidencia de ictus y de enfermedad coronaria, como han demostrado numerosos ensayos clínicos. La combinación de tiazidas con otros antihipertensivos aumenta su eficacia. El efecto adverso más común es la hipopotasemia, por lo que deben vigilarse los valores plasmáticos de potasio. Dado que muchos pacientes no alcanzan el objetivo terapéutico con un solo fármaco, si no existen contraindicaciones, debería incluirse un diurético en cualquier pauta terapéutica que asocie fármacos antihipertensivos (AU)

Thiazides are the most commonly recommended treatment for hypertension because of their low cost, tolerability and efficacy both as monotherapy and in combination with other agents. Although the most commonly used drug is hydrochlorothiazide, there are arguments in favor of its replacement with chlorthalidone. Numerous clinical trials have shown that a diuretic-based strategy is effective in preventing stroke and cardiac disease. Some combinations of thiazide diuretics with an antihypertensive drug of a different class increase antihypertensive efficacy. The most common adverse effect is hypokalemia and consequently plasma potassium levels must be monitored. Because many patients require more than one drug to control their blood pressure, a diuretic should be included in the therapeutic regimen unless contraindicated (AU)