Dual RAAS blockade is desirable in kidney disease: Con

An Overview of Clinically Imperative and Pharmacodynamically Significant Drug Interactions of Renin-Angiotensin-Aldosterone System (RAAS) Blockers

INTRODUCTION

Hypertension is a leading cause of cardiovascular disease and chronic kidney disease, resulting in premature death and disability. The Renin-Angiotensin-Aldosterone System (RAAS) blockers, including Angiotensin-Converting Enzyme (ACE) inhibitors or Angiotensin Receptor Blockers (ARBs), are used as first-line antihypertensive therapy to treat hypertensive patients with comorbidities, including diabetes, ischemic heart disease, heart failure, and chronic kidney disease. The use of RAS blockers is associated with the risks, such as hyperkalemia, angioedema, etc. The drugs potentiating them interact pharmacodynamically, resulting in adverse consequences. This review article focuses on the clinically important drug interactions of RAAS blockers.

MATERIALS AND METHODS

The electronic databases, such as Medline/PubMed Central/PubMed, Google Scholar, ScienceDirect, Cochrane Library, Directory of Open Access Journals (DOAJ), Embase, and reference lists were searched to identify relevant articles.

RESULTS

The risk of hyperkalemia may be enhanced potentially in patients receiving a RAS blocker and potassium-sparing diuretics, potassium supplements, trimethoprim, adrenergic betablockers, antifungal agents, calcineurin inhibitors, pentamidine, heparins or an NSAID, concomitantly. The patients taking ACE inhibitors and mTOR inhibitors, DPP4 inhibitors, alteplase, or sacubitril/valsartan concurrently may be at increased risk of developing angioedema.

CONCLUSION

Clinicians, pharmacists, and other healthcare practitioners should be accountable for medication safety. To avoid adverse implications, prescribers and pharmacists must be aware of the drugs that interact with RAAS blockers.

The dilemma of dual renin-angiotensin system blockade in chronic kidney disease: why beneficial in animal experiments but not in the clinic?

Drugs interfering with the renin-angiotensin-aldosterone system (RAAS) improved the prognosis in patients with hypertension, heart failure, diabetes and chronic kidney disease. However, combining different drugs brought no further benefit while increasing the risk of hyperkalemia, hypotension and acute renal failure. This was so with combining angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptors type 1 antagonists (ARB). Dissimilarly, in animal disease models this dual therapy proved clearly superior to single drug treatment and became the optimal standard regime for comparison with other treatments. This review analyzes the causes of the discrepancy of effects of the dual therapy between animal experiments versus clinical studies, and is focused on the outcomes in chronic kidney disease. Discussed is the role of species differences in RAAS, of the variability of the disease features in humans versus relative stability in animals, of the genetic uniformity in the animals but not in humans, and of the biased publication habits of experimental versus clinical studies. We attempt to understand the causes and reconcile the discordant findings and suggest to what extent dual RAAS inhibition should be continued in animal experiments and why its application in the clinics should be limited to strictly selected groups of patients.

Nephroprotective action of renin-angiotensin-aldosterone system blockade in chronic kidney disease patients: the landscape after ALTITUDE and VA NEPHRON-D trails

The intervention in the renin-angiotensin-aldosterone system (RAAS) is currently the most effective strategy that combines blood pressure lowering and renoprotection. Several large, randomized, controlled trials evidenced the renoprotective potential of the angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) in nephropathies of almost any etiology. Mineralocorticoid receptor antagonists and direct renin inhibitor, aliskiren, as add-on treatments to standard therapy including the optimal dose of ACEIs or ARBs reduce albuminuria or proteinuria and slow development of renal dysfunction more than placebo. No clinical evidence is available however about whether these strategies may influence on long-term kidney outcome. Three recent trials suggested that aggressive RAAS blockade, that is, combination of 2 RAAS-blocking agents, does not decrease cardiovascular and renal morbidity and may carry an increased risk of serious complications. This article reviews an evidence-based approach on the use of RAAS-inhibiting agents in chronic kidney disease and considers the implementation of dual RAAS blockade with reference to the results of ALTITUDE and VA NEPHRON-D trails aiming to aid clinicians in their treatment decisions for patients with chronic kidney disease.

Chronic kidney disease: a new look at pathogenetic mechanisms and treatment options

The concept of renoprotection has evolved significantly, driven by improved understanding of the pathophysiology of chronic kidney disease (CKD) and the advent of novel treatment options. Glomerular hyperfiltration, hypertension and proteinuria represent key mediators of CKD progression. It is increasingly recognized that proteinuria may actually be pathological and etiological in CKD progression and not just symptomatic. It initiates a sequence of events involving activation of proinflammatory and profibrotic signaling pathways in proximal tubular epithelial cells with transmission of the disease to the tubulointerstitium and progression to end-stage kidney disease (ESKD). Although the etiology and epidemiology of pediatric CKD differs to that in adults, studies in the various animal models of kidney disease, from obstructive uropathy to glomerulonephritis, have revealed that many common proinflammatory and profibrotic pathways are induced in progressive proteinuric CKD, irrespective of the primary disease. This pathomechanistic overlap therefore translates into the potential for common treatment targets for a wide spectrum of kidney diseases. In this review we therefore discuss the experimental and clinical evidence for an array of prospective future drug treatments of CKD progression. While conceptually promising, clear definitive evidence beyond preclinical data does not exist for many of these treatments, and others are limited by serious adverse effects. More studies are needed before general recommendations can be given.

Clinical challenges in diagnosis and management of diabetic kidney disease

Diabetic kidney disease (DKD) is a major and increasing worldwide public health issue. There is a great need for implementing treatments that either prevent or significantly slow the progression of DKD. Although there have been significant improvements in management, the increasing numbers of patients with DKD illustrate that current management is not wholly adequate. The reasons for suboptimal management include the lack of early diagnosis, lack of aggressive interventions, and lack of understanding about which interventions are most successful. There are a number of challenges and controversies regarding the current management of patients with DKD. Understanding of these issues is needed in order to provide the best care to patients with DKD. This article describes some of the clinically important challenges associated with DKD: the current epidemiology and cost burden and the role of biopsy in the diagnosis of DKD. Treatment controversies regarding current pharmacologic and nonpharmacologic approaches are reviewed and recommendations based on the published literature are made.

Aliskiren add-on therapy effectively reduces proteinuria in chronic kidney disease: an open-label prospective trial

INTRODUCTION

The combination therapy of aliskiren and renin-angiotensin-aldosterone system (RAAS) blocker in chronic kidney disease (CKD) is controversial. Whether such dual blockade can effectively apply to patients with CKD irrespective of stage and amount of proteinuria remains uncertain.

METHODS

We added aliskiren at a dosage of 150 mg/day for six months in 103 Chinese CKD patients who had been treated with angiotensin converting enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs) and still had significant proteinuria or uncontrolled hypertension. Blood pressure, serum creatinine, estimated glomerular filtration rate (eGFR), potassium, and spot urine protein-to-creatinine ratio (UPCR) were measured at three and six months after aliskiren add-on therapy and compared with baseline.

RESULTS

The combination of aliskiren and ACEi or ARB significantly reduced UPCR by 23% (p=0.001) and mean arterial pressure by 7.9 ± 13.8 mmHg (p<0.001) at six months. Twenty-five percent of subjects had a greater than 50% reduction in UPCR. No significant changes in eGFR and serum potassium level were noted at six months.

CONCLUSIONS

Adding aliskiren on ACEi or ARB in CKD patients, both in diabetes and non-diabetes, has a favorable effect on reducing residual proteinuria and inadequately controlled blood pressure.

Juxtaglomerular apparatus hyperplasia under dual angiotensin blockade. A footprint of adequate RAS inhibition or a concern for renal fibrosis?

Background

Dual renin-angiotensin system blockade with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers has been advocated to minimize proteinuria. However, recent trials have questioned the renal safety of this approach. Our understanding on the molecular effects of dual blockade in humans is incomplete.

Case presentation

We present a patient with corticoid resistant nephrotic syndrome who developed marked juxtaglomerular apparatus hyperplasia and renin expression in the context of dual angiotensin system blockade.

Conclusions

Although renin may have profibrotic effects mediated by (pro)renin receptor activation, this report raises questions on the potential consequences of local renin activation on chronic kidney disease in patients with dual angiotensin blockade.

Nephrotic syndrome in dogs: clinical features and evidence-based treatment considerations

Nephrotic syndrome (NS), defined as the concurrent presence of hypoalbuminemia, proteinuria, hyperlipidemia, and fluid accumulation in interstitial spaces and/or body cavities, is a rare complication of glomerular disease in dogs, cats, and people. Affected animals frequently have markedly abnormal urine protein:creatinine ratios because of urinary loss of large amounts of protein; however, hypoalbuminemia-associated decreased plasma oncotic pressure is insufficient to explain fluid extravasation in most laboratory models, and, instead, either aberrant renal tubule retention of sodium with resultant increase in hydrostatic pressure or a systemic increase in vascular permeability may be the primary defects responsible for development of NS. Factors associated with NS in people (including "nephrotic-range" serum albumin concentration and urine protein concentration, and particular glomerular disease subtypes) have been assumed previously to also be important in dogs, although descriptions were limited to those patients included in case series of glomerular disease, and sporadic case reports. However, case-control comparison of larger cohorts of dogs with nephrotic versus nonnephrotic glomerular disease more recently suggests that predisposing factors and concurrent clinicopathologic abnormalities differ from those typically encountered in people with nephrotic syndrome, although case progression and negative effect on patient outcome are similar. This article briefly reviews major current theories and supporting evidence on the pathogenesis of NS, followed by an overview on the clinical features of this syndrome in dogs with glomerular disease. The authors also offer evidence-based and experience-based treatment recommendations that are based on minimizing the suspected dysregulation of the renin-angiotensin-aldosterone axis in affected dogs.