Effectiveness of chlorthalidone/amiloride versus losartan in patients with stage I hypertension and diabetes mellitus: results from the PREVER-treatment randomized controlled trial.

AIMS: To compare the blood pressure (BP)-lowering efficacy of a chlorthalidone/amiloride combination pill with losartan, during initial management of JNC 7 Stage I hypertension in patients with type 2 diabetes mellitus. METHODS: In an a priori subgroup analysis of a randomized, double-blind, controlled trial, volunteers aged 30-70 years, with stage I hypertension and diabetes mellitus, were randomized to 12.5/2.5 mg of chlorthalidone/amiloride (N = 47) or 50 mg of losartan (N = 50), and followed for 18 months in 21 clinical centers. If BP remained uncontrolled after three months, study medication dose was doubled, and if uncontrolled after six months, amlodipine (5 and 10 mg) and propranolol (40 and 80 mg BID) were added as open label drugs in a progressive fashion. RESULTS: Systolic BP decreased to a greater extent in participants allocated to diuretics compared to losartan (P < 0.001). After 18 months of follow-up, systolic BP was 128.4 ± 10.3 mmHg in the diuretic group versus 133.5 ± 8.0 in the losartan group (P < 0.01). In the diuretic group, 36 out of 43 participants (83.7%) had a JNC 7 normal BP, compared to 31/47 (66%) in the losartan group (P = 0.089). Serum cholesterol was higher in the diuretic arm at the end of the trial. Other biochemical parameters and reports of adverse events did not differ by treatment. CONCLUSIONS: Treatment of hypertension based on a combination of chlorthalidone and amiloride is more effective for BP lowering compared to losartan in patients with diabetes mellitus and hypertension. TRIAL REGISTRATION: Clinical trials registration number: NCT00971165.

Failed Neuroprotection of Combined Inhibition of L-Type and ASIC1a Calcium Channels with Nimodipine and Amiloride.

Effective pharmacological neuroprotection is one of the most desired aims in modern medicine. We postulated that a combination of two clinically used drugs-nimodipine (L-Type voltage-gated calcium channel blocker) and amiloride (acid-sensing ion channel inhibitor)-might act synergistically in an experimental model of ischaemia, targeting the intracellular rise in calcium as a pathway in neuronal cell death. We used organotypic hippocampal slices of mice pups and a well-established regimen of oxygen-glucose deprivation (OGD) to assess a possible neuroprotective effect. Neither nimodipine (at 10 or 20 µM) alone or in combination with amiloride (at 100 µM) showed any amelioration. Dissolved at 2.0 Vol.% dimethyl-sulfoxide (DMSO), the combination of both components even increased cell damage (p = 0.0001), an effect not observed with amiloride alone. We conclude that neither amiloride nor nimodipine do offer neuroprotection in an in vitro ischaemia model. On a technical note, the use of DMSO should be carefully evaluated in neuroprotective experiments, since it possibly alters cell damage.

Amiloride: A review.

Amiloride is a potassium retaining diuretic and natriuretic which acts by reversibly blocking luminal epithelial sodium channels (ENaCs) in the late distal tubule and collecting duct. Amiloride is indicated in oedematous states, and for potassium conservation adjunctive to thiazide or loop diuretics for hypertension, congestive heart failure and hepatic cirrhosis with ascites. Historical studies on its use in hypertension were poorly controlled and there is insufficient data on dose-response. It is clearly highly effective in combination with thiazide diuretics where it counteracts the adverse metabolic effects of the thiazides and its use in the Medical Research Council Trial of Older Hypertensive Patients, demonstrated convincing outcome benefits on stroke and coronary events. Recently it has been shown to be as effective as spironolactone in resistant hypertension but there is a real need to establish its potential role in the much larger number of patients with mild to moderate hypertension in whom there is a paucity of information with amiloride particularly across an extended dose range.

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.

Echocardiographic Left Ventricular Reverse Remodeling After 18 Months of Antihypertensive Treatment in Stage I Hypertension. Results From the Prever-Treatment Study.

BACKGROUND: Antihypertensive treatment improves echocardiographic parameters of hypertensive target organ damage in stage II hypertension, but less is known about the effects in stage I hypertension. METHODS: In a cohort study nested in the randomized double-blind trial PREVER-treatment, 2-dimensional echocardiograms were performed in 110 individuals, aged 54.8 ± 7.9 years-old, with stage I hypertension at baseline and after 18 months of treatment with chlorthalidone/amiloride or losartan. RESULTS: At baseline, 66 (60%) participants had concentric remodeling. After antihypertensive treatment, systolic (SBP) and diastolic blood pressure (BP) were reduced from 141/90 to 130/83 mm Hg (P = 0.009). There was a significant reduction in left ventricular (LV) mass (LVM) index (82.7 ± 17.1 to 79.2 ± 17.5 g/m2; P = 0.005) and relative wall thickness (0.45 ± 0.06 to 0.42 ± 0.05; P < 0.001), increasing the proportion of participants with normal LV geometry (31% to 49%, P = 0.006). Left atrial (LA) volume index reduced (26.8 ± 7.3 to 24.9 ± 6.5 ml/m2; P = 0.001), and mitral E-wave deceleration time increased (230 ± 46 to 247 ± 67 ms; P = 0.005), but there was no change in other parameters of diastolic function. LVM reduction was significantly higher in the 2 higher tertiles of SBP reduction compared to the lower tertile. CONCLUSIONS: Treatment of patients with stage I hypertension for 18 months promotes favorable effects in the LA and LV remodeling. This improvement in cardiac end-organ damage might be associated with reduction of long term clinical consequences of hypertensive cardiomyopathy, particularly heart failure with preserved ejection fraction.

Amiloride, An Old Diuretic Drug, Is a Potential Therapeutic Agent for Multiple Myeloma.

Purpose: The search for new drugs that control the continuous relapses of multiple myeloma is still required. Here, we report for the first time the potent antimyeloma activity of amiloride, an old potassium-sparing diuretic approved for the treatment of hypertension and edema due to heart failure.Experimental Design: Myeloma cell lines and primary samples were used to evaluate cytotoxicity of amiloride. In vivo studies were carried out in a xenograft mouse model. The mechanisms of action were investigated using RNA-Seq experiments, qRT-PCR, immunoblotting, and immunofluorescence assays.Results: Amiloride-induced apoptosis was observed in a broad panel of multiple myeloma cell lines and in a xenograft mouse model. Moreover, amiloride also had a synergistic effect when combined with dexamethasone, melphalan, lenalidomide, and pomalidomide. RNA-Seq experiments showed that amiloride not only significantly altered the level of transcript isoforms and alternative splicing events, but also deregulated the spliceosomal machinery. In addition, disruption of the splicing machinery in immunofluorescence studies was associated with the inhibition of myeloma cell viability after amiloride exposure. Although amiloride was able to induce apoptosis in myeloma cells lacking p53 expression, activation of p53 signaling was observed in wild-type and mutated TP53 cells after amiloride exposure. On the other hand, we did not find a significant systemic toxicity in mice treated with amiloride.Conclusions: Overall, our results demonstrate the antimyeloma activity of amiloride and provide a mechanistic rationale for its use as an alternative treatment option for relapsed multiple myeloma patients, especially those with 17p deletion or TP53 mutations that are resistant to current therapies. Clin Cancer Res; 23(21); 6602-15. ©2017 AACR.

Changes in selected metabolic parameters in patients over 65 receiving hydrochlorothiazide plus amiloride, atenolol or placebo in the MRC elderly trial.

BACKGROUND: Treatment of hypertension reduces incidence of stroke, myocardial infarction and heart failure perhaps partly by controlling different metabolic parameters. There is limited information regarding the changes in potassium, sodium, weight, cholesterol and glucose levels in patients using anti-hypertensives. This study aimed to determine changes in potassium, sodium, glucose, cholesterol, weight, urea and urate levels in patients using anti-hypertensives. Furthermore, to describe these changes and differences between the atenolol, hydrochlorothiazide plus amiloride and placebo arms of the Medical Research Council (MRC) elderly randomised controlled trial. METHODS: Patients were randomly allocated to one of the three treatment arms. Measurements were taken at baseline, end of year one and end of year two in 4396 subjects. Linear Mixed Models (LMM) were used to determine the longitudinal profiles of sodium, potassium, weight, cholesterol, glucose, urea and urate. Estimates of changes within groups and difference between groups were obtained. RESULTS: Patients randomised to receive hydrochlorothiazide + amiloride experienced a significantly greater mean reduction in potassium, sodium and weight compared to placebo at end of year one - mean differences in change -0.18 mmol/L, (95 % CI: -0.21, -0.15); -1.45 mmol/L, (95 % CI: -1.62, -1.29) and -0.46 kgs (95 % CI: -0.73, -0.20) respectively, and greater increases in cholesterol, urea and urate - mean differences in change 0.16 mmol/L, (95 % CI: 0.10,0.22); 0.77 mmol/L, (95 % CI: 0.68, 0.87) and 53.10 µmol/L, (95 % CI: 49.35, 56.85) respectively. Changes were in the same direction but smaller in the atenololarm except for potassium and weight (increases). No group differences in glucose were found. CONCLUSION: Results were in line with expectation except for lack of change in glucose in the hydrochlorothiazide + amiloride arms.

Comparison of single and combination diuretics on glucose tolerance (PATHWAY-3): protocol for a randomised double-blind trial in patients with essential hypertension.

INTRODUCTION: Thiazide diuretics are associated with increased risk of diabetes mellitus. This risk may arise from K(+)-depletion. We hypothesised that a K(+)-sparing diuretic will improve glucose tolerance, and that combination of low-dose thiazide with K(+)-sparing diuretic will improve both blood pressure reduction and glucose tolerance, compared to a high-dose thiazide. METHODS AND ANALYSIS: This is a parallel-group, randomised, double-blind, multicentre trial, comparing hydrochlorothiazide 25-50 mg, amiloride 10-20 mg and combination of both diuretics at half these doses. A single-blind placebo run-in of 1 month is followed by 24 weeks of blinded active treatment. There is forced dose-doubling after 3 months. The Primary end point is the blood glucose 2 h after oral ingestion of a 75 g glucose drink (OGTT), following overnight fasting. The primary outcome is the difference between 2 h glucose at weeks 0, 12 and 24. Secondary outcomes include the changes in home systolic blood pressure (BP) and glycated haemoglobin and prediction of response by baseline plasma renin. Eligibility criteria are: age 18-79, systolic BP on permitted background treatment ≥ 140 mm Hg and home BP ≥ 130 mm Hg and one component of the metabolic syndrome additional to hypertension. Principal exclusions are diabetes, estimated-glomerular filtration rate <45 mL/min, abnormal plasma K(+), clinic SBP >200 mm Hg or DBP >120 mm Hg (box 2). The sample size calculation indicates that 486 patients will give 80% power at α=0.01 to detect a difference in means of 1 mmol/L (SD=2.2) between 2 h glucose on hydrochlorothiazide and comparators. ETHICS AND DISSEMINATION: PATHWAY-3 was approved by Cambridge South Ethics Committee, number 09/H035/19. The trial results will be published in a peer-reviewed scientific journal. TRIAL REGISTRATION NUMBERS: Eudract number 2009-010068-41 and clinical trials registration number: NCT02351973.

NVP-QBE170: an inhaled blocker of the epithelial sodium channel with a reduced potential to induce hyperkalaemia.

BACKGROUND AND PURPOSE: Inhaled amiloride, a blocker of the epithelial sodium channel (ENaC), enhances mucociliary clearance (MCC) in cystic fibrosis (CF) patients. However, the dose of amiloride is limited by the mechanism-based side effect of hyperkalaemia resulting from renal ENaC blockade. Inhaled ENaC blockers with a reduced potential to induce hyperkalaemia provide a therapeutic strategy to improve mucosal hydration and MCC in the lungs of CF patients. The present study describes the preclinical profile of a novel ENaC blocker, NVP-QBE170, designed for inhaled delivery, with a reduced potential to induce hyperkalaemia. EXPERIMENTAL APPROACH: The in vitro potency and duration of action of NVP-QBE170 were compared with amiloride and a newer ENaC blocker, P552-02, in primary human bronchial epithelial cells (HBECs) by short-circuit current. In vivo efficacy and safety were assessed in guinea pig (tracheal potential difference/hyperkalaemia), rat (hyperkalaemia) and sheep (MCC). KEY RESULTS: In vitro, NVP-QBE170 potently inhibited ENaC function in HBEC and showed a longer duration of action to comparator molecules. In vivo, intratracheal (i.t.) instillation of NVP-QBE170 attenuated ENaC activity in the guinea pig airways with greater potency and duration of action than that of amiloride without inducing hyperkalaemia in either guinea pig or rat. Dry powder inhalation of NVP-QBE170 by conscious sheep increased MCC and was better than inhaled hypertonic saline in terms of efficacy and duration of action. CONCLUSIONS AND IMPLICATIONS: NVP-QBE170 highlights the potential for inhaled ENaC blockers to exhibit efficacy in the airways with a reduced risk of hyperkalaemia, relative to existing compounds.

Indomethacin, amiloride, or eplerenone for treating hypokalemia in Gitelman syndrome.

Patients with Gitelman syndrome (GS), an inherited salt-losing tubulopathy, are usually treated with potassium-sparing diuretics or nonsteroidal anti-inflammatory drugs and oral potassium and magnesium supplementations. However, evidence supporting these treatment options is limited to case series studies. We designed an open-label, randomized, crossover study with blind end point evaluation to compare the efficacy and safety of 6-week treatments with one time daily 75 mg slow-release indomethacin, 150 mg eplerenone, or 20 mg amiloride added to constant potassium and magnesium supplementation in 30 patients with GS (individual participation: 48 weeks). Baseline plasma potassium concentration was 2.8±0.4 mmol/L and increased by 0.38 mmol/L (95% confidence interval [95% CI], 0.23 to 0.53; P<0.001) with indomethacin, 0.15 mmol/L (95% CI, 0.02 to 0.29; P=0.03) with eplerenone, and 0.19 mmol/L (95% CI, 0.05 to 0.33; P<0.01) with amiloride. Fifteen patients became normokalemic: six with indomethacin, three with eplerenone, and six with amiloride. Indomethacin significantly reduced eGFR and plasma renin concentration. Eplerenone and amiloride each increased plasma aldosterone by 3-fold and renin concentration slightly but did not significantly change eGFR. BP did not significantly change. Eight patients discontinued treatment early because of gastrointestinal intolerance to indomethacin (six patients) and hypotension with eplerenone (two patients). In conclusion, each drug increases plasma potassium concentration in patients with GS. Indomethacin was the most effective but can cause gastrointestinal intolerance and decreased eGFR. Amiloride and eplerenone have similar but lower efficacies and increase sodium depletion. The benefit/risk ratio of each drug should be carefully evaluated for each patient.

Arrhythmias and ECG changes in life threatening hyperkalemia in older patients treated by potassium sparing drugs.

BACKGROUND: Severe hyperkalemia is a life threatening condition that can cause fatal rhythm disturbance and terminal heart arrest. The most common cause of hyperkalemia in older patients is that of iatrogenic medication-related etiology due to associated polymorbidity, polypharmacy and reduced reserve metabolic capacity. The aim of this paper is to increase awareness in the clinicians of the risk of hyperkalemia in elderly patients treated by potassium sparing drugs. METHODS AND RESULTS: We present two case reports of hyperkalemia ≥ 9.0 mmol/L induced by potassium sparing medications with cardiac arrhythmias and severe ECG changes including atrial asystole, disturbance of intraventricular conduction and morphological changes such as tenting T waves and deformed wide QRS complexes. The most frequent causes of hyperkalemia in elderly patients are discussed and electrocardiogram changes and arrhythmias in hyperkalemia are analyzed, as well as their treatment and prevention. CONCLUSION: Potassium sparing drug therapy in older persons requires more frequent monitoring especially when drugs or their doses are changed, or during concomitant acute illness.

Myocardial fibrosis and QTc are reduced following treatment with spironolactone or amiloride in stroke survivors: a randomised placebo-controlled cross-over trial.

INTRODUCTION: Myocardial fibrosis is dysrhythmogenic and may contribute to the high incidence of cardiac death in stroke survivors, especially if they have long QTc. We tested the hypothesis that procollagen-1-carboxy terminal peptide (P1CP), a biomarker of myocardial fibrosis, might be improved following treatment with spironolactone or amiloride in stroke survivors. We also tested the hypothesis that both drugs would shorten QTc. STUDY DESIGN: randomised, double-blinded, placebo-controlled, cross-over trial (spironolactone vs. amiloride vs. placebo). Duration of Study: 3 months (1 month per drug). Primary endpoints: P1CP, QTc RESULTS: 11 stroke survivors (5 female), aged 71 ± 4, BP 139/81 mmHg ± 20/11 mmHg, completed the study. Both spironolactone and amiloride significantly reduced P1CP [Spironolactone-Placebo = -24 ug/L, 95% CI = -40 to -6.9; Amiloride-Placebo = -28 ug/L, 95% CI = -44 to -11]. Spironolactone and amiloride both shortened QTc [Spironolactone vs. Placebo=-18 ms(1/2), 95% CI = -36 to -0.55; Amiloride vs Placebo = -25 ms(1/2), 95% CI = -42 to -7.5]. CONCLUSIONS: Procollagen-1-carboxy terminal peptide was reduced following treatment with spironolactone within a month. Further, this is the first study demonstrating amiloride could also improve myocardial fibrosis. The beneficial effects of both drugs on myocardial fibrosis, coupled with their effects on raising potassium translated to a shortening of QTc. Future studies should test the hypothesis that these drugs might reduce the risk of sudden cardiac death in stroke survivors.

A double-blind, placebo-controlled, crossover trial comparing the effects of amiloride and hydrochlorothiazide on glucose tolerance in patients with essential hypertension.

Hypertension guidelines advise limiting the dose of thiazide diuretics and avoiding combination with ß-blockade, because of increased risk of diabetes mellitus. We tested whether changes in the 2-hour oral glucose tolerance test could be detected after 4 weeks of treatment with a thiazide and could be avoided by switching to amiloride. Two double-blind, placebo-controlled, crossover studies were performed. In study 1 (41 patients), we found that changes in glucose during a 2-hour oral glucose tolerance test could be detected after 4 weeks of treatment with bendroflumethiazide. In study 2, 37 patients with essential hypertension received, in random order, 4 weeks of once-daily treatment with hydrochlorothiazide (HCTZ) 25 to 50 mg, nebivolol 5 to 10 mg, combination (HCTZ 25-50 mg+nebivolol 5-10 mg), amiloride (10-20 mg), and placebo. Each drug was force titrated at 2 weeks and separated by a 4-week placebo washout. At each visit, we recorded blood pressure and performed a 75-g oral glucose tolerance test. Primary outcome was the difference in glucose (over the 2 hours of the oral glucose tolerance test) between 0 and 4 weeks, when HCTZ and amiloride were compared by repeated-measures analysis. For similar blood pressure reductions, there were opposite changes in glucose between the 2 diuretics (P<0.0001). Nebivolol did not impair glucose tolerance, either alone or in combination. There was a negative correlation between Δpotassium and Δ2-hour glucose (r=-0.28; P<0.0001). In 2 crossover studies, 4 weeks of treatment with a thiazide diuretic impaired glucose tolerance. No impairment was seen with K(+)-sparing diuretic or ß(1)-selective blockade. Substitution or addition of amiloride may be the solution to preventing thiazide-induced diabetes mellitus.

Combination of amlodipine plus angiotensin receptor blocker or diuretics in high-risk hypertensive patients: a 96-week efficacy and safety study.

BACKGROUND AND OBJECTIVES: Antihypertensive therapy is effective in reducing the risk of major adverse cardiovascular events. However, blood pressure (BP) control rate remains poor and the optimal combination therapy against hypertension is not established in China. The objective of this study was to evaluate the long-term efficacy and safety of two antihypertensive regimens, amlodipine plus telmisartan and amlodipine plus amiloride/hydrochlorothiazide, in patients with essential hypertension and at least one cardiovascular risk factor. METHODS: In a multicenter open-label clinical trial, eligible patients were randomized to receive treatment with amlodipine 2.5-5 mg plus amiloride/hydrochlorothiazide 1.25-2.5 mg/12.5-25 mg (Group A) or amlodipine 2.5-5 mg plus telmisartan 40-80 mg (Group T). If a target BP was not reached, other antihypertensive agents would be added. The target BP was <130/80 mmHg for patients with diabetes mellitus or chronic kidney disease and <140/90 mmHg for others. Efficacy variables were changes from baseline in systolic BP and diastolic BP at the endpoint of 96 weeks. Safety evaluations included monitoring of any adverse events (AEs). RESULTS: Of 13,542 patients randomized, 13,080 (96.6%) completed the study: 6529 in Group A and 6551 in Group T. At endpoint, the BP levels were reduced by 27.4/14.3 mmHg in Group A and 27.1/14.5 mmHg in Group T. The BP control rates were similar for the two therapeutic regimens (87.5% vs 86.1%). Less than 4% of patients in each group discontinued their drugs during follow-up. Peripheral edema was one of the most common AEs, and occurred in only 24 patients in Group A and 19 in Group T. CONCLUSIONS: Long-term combination therapy with amlodipine plus telmisartan or amlodipine plus amiloride/hydrochlorothiazide was not only well tolerated but also efficacious in reducing BP levels with acceptable control rates in the majority of hypertensive patients. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov number NCT01011660.

Antiepileptic intranasal Amiloride loaded mucoadhesive nanoemulsion: development and safety assessment.

Current investigation aimed to develop a novel Amiloride loaded mucoadhesive nanoemulsion formulation for nose-to-brain delivery. Furthermore, nasal irritation study and histopathological examination of the nasal mucosa were also carried out to assess nonirritant nature of the nanoemulsion. The optimized formulation, surface epithelium lining and the granular cellular structure of the nasal mucosa were totally intact, whereas KCl caused major changes in the ultrastructure of mucosa. Amiloride loaded mucoadhesive nanoemulsion formulations are non toxic on nasal mucosa and can be administered by intranasal route for effective treatment of epilepsy.

A comparison between diuretics and angiotensin-receptor blocker agents in patients with stage I hypertension (PREVER-treatment trial): study protocol for a randomized double-blind controlled trial.

BACKGROUND: Cardiovascular disease is the leading cause of death in Brazil, and hypertension is its major risk factor. The benefit of its drug treatment to prevent major cardiovascular events was consistently demonstrated. Angiotensin-receptor blockers (ARB) have been the preferential drugs in the management of hypertension worldwide, despite the absence of any consistent evidence of advantage over older agents, and the concern that they may be associated with lower renal protection and risk for cancer. Diuretics are as efficacious as other agents, are well tolerated, have longer duration of action and low cost, but have been scarcely compared with ARBs. A study comparing diuretic and ARB is therefore warranted. METHODS/DESIGN: This is a randomized, double-blind, clinical trial, comparing the association of chlorthalidone and amiloride with losartan as first drug option in patients aged 30 to 70 years, with stage I hypertension. The primary outcomes will be variation of blood pressure by time, adverse events and development or worsening of microalbuminuria and of left ventricular hypertrophy in the EKG. The secondary outcomes will be fatal or non-fatal cardiovascular events: myocardial infarction, stroke, heart failure, evidence of new subclinical atherosclerosis and sudden death. The study will last 18 months. The sample size will be of 1200 participants for group in order to confer enough power to test for all primary outcomes. The project was approved by the Ethics committee of each participating institution. DISCUSSION: The putative pleiotropic effects of ARB agents, particularly renal protection, have been disputed, and they have been scarcely compared with diuretics in large clinical trials, despite that they have been at least as efficacious as newer agents in managing hypertension. Even if the null hypothesis is not rejected, the information will be useful for health care policy to treat hypertension in Brazil. CLINICAL TRIALS REGISTRATION NUMBER: ClinicalTrials.gov: NCT00971165.

Fidelity variants of RNA dependent RNA polymerases uncover an indirect, mutagenic activity of amiloride compounds.

In a screen for RNA mutagen resistance, we isolated a high fidelity RNA dependent RNA polymerase (RdRp) variant of Coxsackie virus B3 (CVB3). Curiously, this variant A372V is also resistant to amiloride. We hypothesize that amiloride has a previously undescribed mutagenic activity. Indeed, amiloride compounds increase the mutation frequencies of CVB3 and poliovirus and high fidelity variants of both viruses are more resistant to this effect. We hypothesize that this mutagenic activity is mediated through alterations in intracellular ions such as Mg²+ and Mn²+, which in turn increase virus mutation frequency by affecting RdRp fidelity. Furthermore, we show that another amiloride-resistant RdRp variant, S299T, is completely resistant to this mutagenic activity and unaffected by changes in ion concentrations. We show that RdRp variants resist the mutagenic activity of amiloride via two different mechanisms: 1) increased fidelity that generates virus populations presenting lower basal mutation frequencies or 2) resisting changes in divalent cation concentrations that affect polymerase fidelity. Our results uncover a new antiviral approach based on mutagenesis.