The place of diuretics in the treatment of hypertension: a historical review of classical experience over 30 years

Potential role of gene-environment interactions in ion transport mechanisms in the etiology of renal cell cancer

We investigated the ion transport mechanism (ITM) in renal cell cancer (RCC) etiology using gene-environment interactions between candidate single nucleotide polymorphisms (SNPs) and associated environmental factors, including dietary intakes of sodium, potassium and fluid, hypertension and diuretic medication. A literature-based selection of 13 SNPs in ten ITM genes were successfully genotyped in toenail DNA of 3,048 subcohort members and 419 RCC cases from the Netherlands Cohort Study. Diet and lifestyle were measured with baseline questionnaires. Cox regression analyses were conducted for main effects and gene-environment interactions. ADD1_rs4961 was significantly associated with RCC risk, showing a Hazard Ratio (HR) of 1.24 (95% confidence intervals (CI): 1.01–1.53) for the GT + TT (versus GG) genotype. Four of 65 tested gene-environment interactions were statistically significant. Three of these interactions clustered in SLC9A3_rs4957061, including the ones with fluid and potassium intake, and diuretic medication. For fluid intake, the RCC risk was significantly lower for high versus low intake in participants with the CC genotype (HR(95% CI): 0.47(0.26–0.86)), but not for the CT + TT genotype (P-interaction = 0.002). None of the main genetic effects and gene-environment interactions remained significant after adjustment for multiple testing. Data do not support the general hypothesis that the ITM is a disease mechanism in RCC etiology.

Efficacy and safety of ipragliflozin in patients with type 2 diabetes inadequately controlled on metformin: a dose-finding study

AIMS

Ipragliflozin is a novel, selective inhibitor of sodium glucose co-transporter 2 (SGLT2 inhibitor) in clinical development for type 2 diabetes mellitus (T2DM) treatment. This study assessed the efficacy and safety of different doses of ipragliflozin.

METHODS

In a 12-week, multicentre, double-blind, randomized, placebo-controlled, dose-finding study patients with inadequate glycaemic control on metformin monotherapy (≥1500 mg/day) were randomized to one of four ipragliflozin treatment groups (12.5, 50, 150 or 300 mg once daily) or placebo. Primary efficacy outcome was mean change from baseline in haemoglobin A1c (HbA1c) compared to placebo at week 12. Adverse events (AEs), vital signs and laboratory safety measurements were assessed.

RESULTS

Ipragliflozin dose dependently decreased HbA1c from baseline to week 12 compared to placebo (-0.22, -0.34, -0.40 and -0.48% for ipragliflozin 12.5, 50, 150 and 300 mg, respectively). Decreases in body weight and blood pressure were observed for all ipragliflozin groups. AEs occurred in 39.7-51.4% of the ipragliflozin groups and 39.4% of placebo patients. Urinary tract infections (1.4-6.9 vs. 6.1%), genital infections (0-4.3 vs. 1.5%) and hypoglycaemia (0-5.9 vs. 3.0%) were similar in the ipragliflozin and placebo groups, respectively, without dose dependency. There were no clinically relevant effects on other safety measurements.

CONCLUSIONS

Ipragliflozin treatment improved glycaemic control when added to metformin therapy and may be associated with weight loss and reductions in blood pressure compared to placebo. No safety or tolerability concerns were identified at any of the tested doses supporting the further development of ipragliflozin at ≥50 mg doses in T2DM patients.

A comparison of the natriuretic and kaliuretic effects of cicletanine and hydrochlorothiazide in prehypertensive and hypertensive humans

OBJECTIVES

The aim of this study was to compare the single-dose effects of thiazide-type diuretics cicletanine and hydrochlorothiazide (HCTZ), on natriuresis and kaliuresis in prehypertensive and treatment-naïve, stage 1 hypertensive patients and to explore the impact of GRK4 gene polymorphisms on thiazide-induced urinary electrolyte excretion.

METHODS

The study was a randomized, double-blind, placebo-controlled, three-period, four-treatment, balanced incomplete block, cross-over study in male patients assigned to treatment sequences consisting of placebo, cicletanine 50 mg, cicletanine 150 mg, and HCTZ 25 mg, doses used to treat hypertension. Cumulative urine samples were collected predosing and over 24 h after dosing in each period to compare urine electrolyte excretion profiles of potassium (UKV), sodium (UNaV), magnesium, calcium, phosphate, chloride, and pH among groups. Each treatment was administered to 18 different patients in each period, and an equal number of patients had less than and at least three GRK4 allele variants.

RESULTS

Compared with placebo, mean UKV was significantly increased with HCTZ 25 mg (12.7 mmol/day; P ≤ 0.001), cicletanine 50 mg (4.6 mmol/day; P = 0.026), and cicletanine 150 mg (5.5 mmol/day; P = 0.011), and mean UNaV was significantly increased with HCTZ 25 mg (102.2 mmol/day; P ≤ 0.001), cicletanine 50 mg (21.7 mmol/day; P = 0.005), and cicletanine 150 mg (57.9 mmol/day; P ≤ 0.001).

CONCLUSION

All treatments had more natriuresis, diuresis, and kaliuresis than placebo, and both doses of cicletanine had less kaliuresis than HCTZ. These findings suggest that cicletanine is a favorable and well tolerated option for the treatment of hypertension with an improved safety profile compared with HCTZ.

Is newer always better? Re-evaluating the benefits of newer pharmaceuticals

Whether newer pharmaceuticals justify their higher costs by reducing other health expenditures has generated significant debate. We replicate a frequently cited paper by Lichtenberg on drug "offsets" and find the results disappear using a more appropriate model or updated dataset. Further, we test the suitability of similar methods using newer hypertension drugs. We find our observational results run counter to well-established clinical evidence on comparative efficacy and conclude that our model, as well as other studies that do not adequately control for unobserved characteristics that jointly determine drug choice and health expenditures, are likely subject to significant bias.

Effect of dapagliflozin in patients with type 2 diabetes who have inadequate glycaemic control with metformin: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Correction of hyperglycaemia and prevention of glucotoxicity are important objectives in the management of type 2 diabetes. Dapagliflozin, a selective sodium-glucose cotransporter-2 inhibitor, reduces renal glucose reabsorption in an insulin-independent manner. We assessed the efficacy and safety of dapagliflozin in patients who have inadequate glycaemic control with metformin.

METHODS

In this phase 3, multicentre, double-blind, parallel-group, placebo-controlled trial, 546 adults with type 2 diabetes who were receiving daily metformin (>/=1500 mg per day) and had inadequate glycaemic control were randomly assigned to receive one of three doses of dapagliflozin (2.5 mg, n=137; 5 mg, n=137; or 10 mg, n=135) or placebo (n=137) orally once daily. Randomisation was computer generated and stratified by site, implemented with a central, telephone-based interactive voice response system. Patients continued to receive their pre-study metformin dosing. The primary outcome was change from baseline in haemoglobin A(1c)(HbA(1c)) at 24 weeks. All randomised patients who received at least one dose of double-blind study medication and who had both a baseline and at least one post-baseline measurement (last observation carried forward) were included in the analysis. Data were analysed by use of ANCOVA models. This trial is registered with ClinicalTrials.gov, number NCT00528879.

FINDINGS

534 patients were included in analysis of the primary endpoint (dapagliflozin 2.5 mg, n=135; dapagliflozin 5 mg, n=133; dapagliflozin 10 mg, n=132; placebo, n=134). At week 24, mean HbA(1c) had decreased by -0.30% (95% CI -0.44 to -0.16) in the placebo group, compared with -0.67% (-0.81 to -0.53, p=0.0002) in the dapagliflozin 2.5 mg group, -0.70% (-0.85 to -0.56, p<0.0001) in the dapagliflozin 5 mg group, and -0.84% (-0.98 to -0.70, p<0.0001) in the dapagliflozin 10 mg group. Symptoms of hypoglycaemia occurred in similar proportions of patients in the dapagliflozin (2-4%) and placebo groups (3%). Signs, symptoms, and other reports suggestive of genital infections were more frequent in the dapagliflozin groups (2.5 mg, 11 patients [8%]; 5 mg, 18 [13%]; 10 mg, 12 [9%]) than in the placebo group (seven [5%]). 17 patients had serious adverse events (four in each of the dapagliflozin groups and five in the placebo group).

INTERPRETATION

Addition of dapagliflozin to metformin provides a new therapeutic option for treatment of type 2 diabetes in patients who have inadequate glycaemic control with metformin alone.

FUNDING

Bristol-Myers Squibb and AstraZeneca.

Effects of perindopril and hydrochlorothiazide on selected indices of oxidative stress in the blood of elderly patients with essential hypertension

1. The aim of the present study was to determine the effect of hypotensive therapy with a diuretic (hydrochlorothiazide) and an angiotensin-converting enzyme inhibitor (perindopril) on selected oxidative stress parameters in the blood of elderly patients with essential hypertension. 2. Studies were performed in 45 elderly patients with essential hypertension at baseline and after the 45th day of perindopril (n = 25) or hydrochlorothiazide (n = 20) therapy, as well as in 25 young and 25 elderly normotensive subjects. The following parameters were measured: systolic and diastolic blood pressure, nitric oxide (NO), carbonyl groups and malondialdehyde (MDA) concentrations, as well as the activity of ceruloplasmin (Cp) oxidase, Cu-Zn superoxide dismutase (SOD-1) and catalase (CAT). 3. The activity of SOD-1 and NO levels were reduced with age. 4. Compared with elderly controls, hypertensive subjects showed increases in baseline MDA, carbonyl group concentrations and Cp oxidase activity and decreases in NO levels and SOD-1 and CAT activities. 5. Treatment with perindopril, but not hydrochlorothiazide, resulted in significant increases in SOD-1 and CAT activities and decreases in MDA concentration and Cp oxidase activity. Both therapies decreased the level of carbonyl groups and increased NO levels. 6. Angiotensin-converting enzyme inhibitor therapy has significant anti-oxidant effects that may be important in the treatment of elderly patients with essential hypertension.

Effects of cicletanine on the progression of renal failure in 5/6 nephrectomized hypertensive rats

1. The effect of cicletanine, a novel antihypertensive agent with natriuretic activity, on blood pressure and progression of renal failure of 5/6 nephrectomized spontaneously hypertensive rats with salt loading was examined. 2. All nephrectomized rats were randomly assigned to one of four groups and their diet was changed from a normal- to a high-salt (5.5% NaCl) diet for the next 10 weeks. Either 10 or 50 mg/kg per day cicletanine (low- and high-dose cicletanine, respectively) or 10 mg/kg per day trichlormethiazide were administered to rats during this period once a day. During the experimental period, urine volume, urinary excretion of sodium, protein, prostaglandin (PG) E2 and 6-keto-PGF1 alpha and systolic blood pressure (SBP) were measured every 2 weeks. 3. Systolic blood pressure was significantly reduced by the administration of trichlormethiazide and the higher dose of cicletanine, but not by the lower dose of cicletanine. 4. In contrast with changes to SBP, levels of serum creatinine in rats treated with both doses of cicletanine were significantly lower than in controls (0.57 +/- 0.12, 0.78 +/- 0.12 and 1.68 +/- 0.26 mg/dL for high- and low-dose cicletanine and control, respectively). 5. Urinary excretion of both PGE2 and 6-keto-PGF1 alpha were significantly increased in groups treated with high and low doses of cicletanine compared with control. In rats treated with trichlormethiazide, PGE2 and 6-keto-PGF1 alpha levels were significantly decreased compared with control. 6. In contrast with changes in SBP, marked glomerular sclerosis with hyalinosis found in the control group was not ameliorated by trichlormethiazide treatment. These changes were not observed in rats treated with low- and high-dose cicletanine, particularly those treated with the higher dose of cicletanine. 7. These data suggest that administration of cicletanine has a beneficial protective effect regarding the progression of renal failure, regardless of the level of blood pressure, through a direct and/or indirect action on the glomerulus.

Edema and principles of diuretic use

Diuretics have changed the approach to many disease and have turned once fatal conditions into tolerable ones. Treatment of salt and water overload and edema can be quite satisfying for the clinician as long as the patient is closely watched for side effects. Thiazide diuretics have their greatest use in hypertension, loop diuretics in edema and congestive heart failure, CA inhibitors in glaucoma and altitude sickness, potassium-sparing diuretics in hypokalemia induced by other diuretics and ascites, and osmotic diuretics in acute renal failure and dialysis. They are among the most widely prescribed medications in the world today and rightly have a prominent place in the armamentarium against disease.

Which diuretic to use?

The choice of a diuretic depends on knowledge of its efficacy in different disease states as well as the complications associated with its use. However, efficacy of the various diuretic agents as determined in healthy subjects may not always be applicable to the sick patient. The thiazide group appears to be the main offender with regard to hypokalemia and metabolic upsets; these complications seem to stem from long-term use and high dosages. Interest has been expressed on the influence of diuretic induced hypokalemia (and intracellular potassium deficiency) in inducing insulin resistance. The lipid abnormalities may arise as a result of this resistance or may be consequent on hyperinsulinemia from other as yet undetermined mechanisms. In addition, hypertension per se may be associated with insulin resistance. It is interesting to speculate that diuretics, which are commonly used in the treatment of hypertension, may, in some way, perhaps via the induction of hypokalemia, unmask this resistance.