Position of indapamide,a diuretic with vasorelaxant activities,in antihypertensive therapy

Opana^® ER (oxymorphone extended release [ER]) is a new oral long-acting formulation indicated for the treatment of moderate to severe chronic pain. Because the ER matrix slowly releases oxymorphone over 12 h, consistent plasma levels are produced with low peak-to-trough fluctuations. Oxymorphone ER is the only long-acting opioid that contains oxymorphone, which exhibits some distinct pharmacologic properties compared with most other opioids, including a longer half-life, higher affinity for the µ-opioid receptor, and lack of interaction with the CYPP450 drug-metabolizing system. With a safety and tolerability profile similar to other opioids and documented efficacy in several models of chronic pain (low back, cancer, and osteoarthritis), oxymorphone ER provides a new option for clinicians and patients in the treatment of chronic pain.     

Beta-Blockers and Diuretics the Happhy and Maphy Studies

The question whether initial antihypertensive treatment with a beta-blocker prevents hypertensive complications better than initial treatment with a non-betablocker, mainly diuretic based treatment, has been studied in recent large-scale studies like the Medical Research Council (MRC) trial, the International Prospective Primary Prevention Study in Hypertension (IPPPSH), the Heart Attack Primary Prevention in Hypertension (HAPPHY) study and the Metoprolol Atherosclerosis Prevention in Hypertensives (MAPHY) study.

The first three studies were unable to find a more beneficial effect of beta-blockers than of thiazide diuretics. The MAPHY study, however, found a lower total mortality, in the metoprolol treated group than in the diuretic treated. As the HAPPHY and MAPHY studies share a substantial part of patient-years and number of deaths, these diverging results have evoked confusion and debate. This paper presents the main results of both studies and discusses the possible reasons for the different outcome.     

Effect of low-dose thiazide diuretics on plasma lipids: results from a double-blind,randomized clinical trial in older men and women

OBJECTIVES: To determine the effects of low doses of hydrochlorothiazide (HCTZ) on plasma lipids in healthy older men and women. DESIGN: Randomized, double-blind, placebo-controlled clinical trial for 3 years followed by a 1 year extension without medication. SETTING: Research clinic of a nonprofit health maintenance organization. PARTICIPANTS: Two hundred five women and 115 men aged 60 to 79 with normal blood pressure, bone density within two standard deviations of mean for age, and low-density lipoprotein cholesterol (LDL-C) levels less than 190 mg/dL. INTERVENTION: Placebo or HCTZ 12.5 or 25 mg/d. MEASUREMENTS: Plasma cholesterol, LDL-C, high-density lipoprotein cholesterol, triglycerides. RESULTS: There were no significant differences in the change in the plasma lipids between placebo and either group. The mean changes +/- standard deviation in LDL-C after 3 years in men were -5.2 +/- 3.9 mg/dL (placebo), -4.6 +/- 3.7 (12.5 mg), and 1.1 +/- 3.8 (25 mg) and in women were 1.3 +/- 2.8 (placebo), -1.1 +/- 2.8 (12.5 mg), and -6.8 +/- 2.8 (25 mg). No significant differences were seen when analysis was done only for subjects who adhered to study medication. CONCLUSION: This study provides evidence that low doses of thiazide diuretics have minimal effects on cholesterol metabolism in healthy older adults. Therefore, effects on lipid levels need not limit use of thiazides for prevention of osteoporotic fractures.     

Angiotensin II signaling increases activity of the renal Na-Cl cotransporter through a WNK4-SPAK-dependent pathway

Mutations in the kinase WNK4 cause pseudohypoaldosteronism type II (PHAII), a syndrome featuring hypertension and high serum K⁺ levels (hyperkalemia). WNK4 has distinct functional states that regulate the balance between renal salt reabsorption and K⁺ secretion by modulating the activities of renal transporters and channels, including the Na-Cl cotransporter NCC and the K⁺ channel ROMK. WNK4's functions could enable differential responses to intravascular volume depletion (hypovolemia) and hyperkalemia. Because hypovolemia is uniquely associated with high angiotensin II (AngII) levels, AngII signaling might modulate WNK4 activity. We show that AngII signaling in Xenopus oocytes increases NCC activity by abrogating WNK4's inhibition of NCC but does not alter WNK4's inhibition of ROMK. This effect requires AngII, its receptor AT1R, and WNK4, and is prevented by the AT1R inhibitor losartan. NCC activity is also increased by WNK4 harboring mutations found in PHAII, and this activity cannot be further augmented by AngII signaling, consistent with PHAII mutations providing constitutive activation of the signaling pathway between AT1R and NCC. AngII's effect on NCC is also dependent on the kinase SPAK because dominant-negative SPAK or elimination of the SPAK binding motif in NCC prevent activation of NCC by AngII signaling. These effects extend to mammalian cells. AngII increases phosphorylation of specific sites on SPAK and NCC that are necessary for activation of each in mpkDCT cells. These findings place WNK4 in the signaling pathway between AngII and NCC, and provide a mechanism by which hypovolemia maximizes renal salt reabsoprtion without concomitantly increasing K⁺ secretion.     

复方缬沙坦治疗轻中度原发性高血压患者的疗效观察

目的评价复方缬沙坦（缬沙坦80mg／氢氯噻嗪12．5mg复方制剂）治疗经单用缬沙坦80mg控制不良的轻、中度原发性高血压患者疗效和安全性。方法采用多中心、双盲、双模拟、随机、活性药物对照、平行试验方法。对经2周洗脱期的轻、中度原发性高血压患者[坐位舒张压≥95mmHg（1mmHg=0．133kPa）且〈110mmHg]采用单药缬沙坦80mg／d治疗4周,在单药导入结束后,坐位舒张压仍〉190mmHg的864例患者按1：1随机、双盲分为复方缬沙坦组或缬沙坦80mg／d组,继续治疗8周。在治疗4周和结束时评估药物安全性及有效性。结果在轻、中度原发性高血压患者中复方缬沙坦每日1次比单用缬沙坦80mg／d血压进一步下降、达标率提高。治疗结束时平均坐位收缩压多降低3．5mmHg,平均坐位舒张压多下降2．2mmHg,血压控制〈140／90mmHg的患者在复方缬沙坦组和单用缬沙坦80mg／d组分别为53．9％及40．9％。结论轻、中度原发性高血压患者采用复方缬沙坦治疗组降压有效率及达标率均优于每日1次服用缬沙坦80mg／d组。复方缬沙坦适用于缬沙坦单药控制不良的轻、中度原发性高血压患者。     

血管紧张素转换酶和醛固酮合成酶基因多态性与氢氯噻嗪降压疗效的关系

目的研究血管紧张素转换酶(ACE)基因I/D多态性和醛固酮合成酶(CYP11B2)基因-344T/C多态性与氢氯噻嗪降压疗效的关系。方法829例高血压病(EH)患者同时服用氢氯噻嗪12·5mg(1次/d),6周后资料完整的785例患者按不同ACE基因型和CYP11B2基因型分组,比较不同基因型和不同基因型组合间血压下降值有无差别。结果服用氢氯噻嗪6周后,ACE基因II、ID、DD型患者收缩压分别下降(5·1±14·8)mmHg(1mmHg=0·133kPa)、(4·8±16·3)mmHg和(9·4±15·7)mmHg,DD型患者下降值大于II、ID型患者,组间比较差异有统计学意义(P<0·00);CYP11B2基因TT、TC、CC型患者收缩压下降值分别为(5·8±16·2)mmHg、(5·5±14·9)mmHg和(7·6±16·1)mmHg,组间比较差异无统计学意义。DD+CC基因型患者收缩压下降值为(10·6±12·3)mmHg,高于其他基因型组合患者,但差异无统计学意义(P>0·05)。多因素分析结果表明DD基因型和治疗前醛固酮浓度是影响患者坐位收缩压下降的主要因素。结论ACE基因的DD型与氢氯噻嗪的降压疗效相关,CYP11B2基因CC型、DD+CC型患者对氢氯噻嗪的降压反应可能优于其他基因组合患者。     

Antihypertensive drug therapy and the risk of lower extremity amputations in pharmacologically treated type 2 diabetes patients

PURPOSE: The objective of this study was to determine the association between different antihypertensive drug therapies and lower extremity amputations (LEAs) in type 2 diabetes patients. METHODS: Data were obtained from the PHARMO Record Linkage System comprising pharmacy records and data on hospitalisations for all 450,000 residents of eight Dutch cities. In a nested case-control study among 12,140 type 2 diabetes patients who used antihypertensive drugs, 26 cases with a first LEA and 94 controls without a LEA matched on age, sex and calendar time were identified. Logistic regression was used to estimate the relative risk of LEA and to adjust for potential confounding factors. RESULTS: Among type 2 diabetes patients who used antihypertensive drugs, subjects who used thiazide diuretics, alone or in combination, had a higher risk of LEA compared to subjects who used Angiotensin Converting Enzyme (ACE) inhibitor monotherapy (crude odds ratio (OR): 6.11 [95% confidence interval (CI): 1.32-28.27]). The use of thiazide diuretics was also associated with an increased risk of LEA when compared to the use of any non-thiazide antihypertensive drug (adjusted OR: 7.04 [1.10-45.30]). The increased risk of LEA associated with the use of thiazides compared to the use of non-thiazides depended on the duration of use (adjusted OR(< or = 365 days), 4.82 [0.61-38.34] and adjusted OR(>365 days), 26.16 [1.02-674.02], p-trend = 0.01). CONCLUSIONS: Treatment with thiazide diuretics compared to treatment with other antihypertensive drugs was associated with excess amputations in type 2 diabetes patients. Due to several limitations of this study, our findings do not preclude the use of thiazides in type 2 diabetes mellitus patients as yet.     

Antihypertensive,saluretic and hypokalaemic effects of cyclothiazide in comparison with hydrochlorthiazide with amiloride supplement

Summary The antihypertensive, saluretic and hypokalaemic effects of a small dose of cyclothiazide (2.5 mg daily) were compared with those of a conventional dose of an hydrochlorthiazide-amiloride hydrochloride combination (50+5 mg daily). Both preparations were given to 13 patients with mild (WHO I) hypertension in a cross-over manner for six weeks, with an intervening wash-out phase of three weeks. The antihypertensive efficacy of cyclothiazide was well comparable to that of the hydrochlorthiazide-amiloride combination, although cyclothiazide tended to inhibit renal sodium reabsorption less than the combination. Cyclothiazide tended to cause hypokalaemia, apparently due to increased potassium loss, but with the present dosage none of the 13 patients developed marked hypokalaemia (serum potassium less than 3.3 mmol/l). Both drugs led to a comparable increase in serum urate concentration. Neither of the preparations affected creatinine or free-water clearance. The results suggest that even in relatively small doses thiazides effectively decrease blood pressure, and combining thiazides with potassium-sparing diuretics is advantageous only in patients with marked hypokalaemia and its associated risks.     

Effects of Hydroflumethiazide in Congestive Heart Failure: Renal Electrolyte Excretion Related to Urinary Thiazide Excretion and Aldosterone

Abstract: The effect of hydroflumethiazide (HFT) on renal excretion of sodium, chloride, and potassium was studied in congestive heart failure and related to urinary excretion of thiazide and aldosterone. HFT 75 or 150 mg was administered orally once daily for 4 days to 8 male patients with roentgenological evidence of enlarged heart and slight or no peripheral oedema receiving digitalis and controlled diet. Urinary excretion of HFT did not change after repeated doses, whereas urinary excretion of a metabolite increased significantly. Initially, HFT induced a significant increase in the urinary excretion of sodium and potassium. After repeated doses, the natriuretic effect declined gradually in 6 of the patients. There was consistently a small natriuretic effect and a large kaliuretic effect at high serum aldosterone concentrations and high urine aldosterone excretion rates, whereas at low aldosterone levels, there was a wide range in magnitude of these effects. Relationships of the log urinary excretion rate of HFT to the increase in urinary excretion rate of sodium, chloride, and potassium showed positive and significant correlations. It was concluded that reduced natriuretic effect of HFT in congestive heart failure is not due to reduced delivery of thiazide to renal tubular cells but to compensatory adjustments of the kidney in part induced by aldosterone.