Reversible acute renal failure induced by losartan in a renal transplant recipient

Utilisation and Tolerability of Aliskiren in the Primary Care Setting in England

Aliskiren (Rasilez), a direct renin inhibitor, is indicated for the treatment of essential hypertension. A postmarketing prescription-event monitoring (PEM) study was conducted in England to monitor the safety and utilization of aliskiren. Summary statistics and event incidence densities were calculated. The cohort consisted of 6385 individuals with a median age of 68 years (interquartile range, 59-76). Aliskiren was largely prescribed for its licensed indication of hypertension (93.3%) and was reported as "effective" by the prescriber in 77.4% of individuals. Frequently reported clinical events during treatment were diarrhea (3.1% of on-treatment events), malaise/lassitude (3.0%), and nausea/vomiting (1.2%), which were also common reasons for treatment cessation. Renal events were rare, with 24 cases probably or possibly related to aliskiren use, and four of which were classified as acute renal failure using RIFLE (Risk Injury Failure Loss End-Stage Kidney Disease) criteria. These results should be used in conjunction with other clinical and pharmacoepidemiologic studies to optimize the safe prescribing of aliskiren.

Cyclooxygenase-2 inhibitor-associated acute renal failure: case report with rofecoxib and review of the literature

Cyclooxygenase (COX)-2 inhibitors are widely prescribed for their antiinflammatory and analgesic effects. The potential for COX-2 inhibitors to exert deleterious effects on renal function similar to those of traditional nonsteroidal antiinflammatory drugs is not well defined. Until recently, COX-1 was considered responsible for the synthesis of renal prostaglandins. However, COX-2 is also constitutively expressed in the human kidney Clinical studies have reported a significant decrease in glomerular filtration rate in young and elderly sodium-depleted volunteers given COX-2 inhibitors. We describe the case of a 71-year-old woman who developed acute renal failure after receiving a 50-mg dose of the selective COX-2 inhibitor rofecoxib.

Losartan decreases glomerular filtration rate in isolated perfused porcine slaughterhouse kidneys

We investigated whether Losartan, an angiotensin II (Ang II) AT1 receptor antagonist, decreases renal vascular resistance (RVR) and increases glomerular filtration rate (GFR) in isolated perfused porcine slaughterhouse kidneys (11 control experiments and 11 Losartan experiments with 7.5mg Losartan in the preservation solution and 100(g/minute Losartan infused during perfusion). With perfusion, plasma renin activity (PRA) increased markedly from 3 +/- 1 to 90 +/- 17 ng Ang I/ml/h (control), and from 4 +/- 1 to 70 +/- 8 ng Ang I/ml/h (Losartan), plasma Ang II increased from 86 +/- 63 to 482 +/- 111 pg/ml (control), and from 73 +/- 42 to 410 +/- 91 pg/ml (Losartan). The GFR was decreased in Losartan experiments as compared with control experiments (5 +/- 1 versus 10 +/- 2 ml/min/100g kidney wt; p < 0.05). The RVR was the same in both groups (0.2 +/- 0.01 mm Hg/100g kidney wt/min/ml). Tubular sodium reabsorption was decreased in Losartan experiments as compared with control experiments (0.7 +/- 0.1 versus 1.4 +/- 0.3 mmol/min/100g kidney wt). Overall, Losartan accentuated pathophysiological signs of acute renal failure. Although other drugs have to be investigated, these results suggest that porcine slaughterhouse kidneys could be useful as a tool for research in areas such as transplantation and intensive-care medicine.

Haemodynamic effects of valsartan in acute renal ischaemia/reperfusion injury

BACKGROUND

Acute deterioration of renal function is an important side-effect of angiotensin-converting enzyme (ACE) inhibitors, especially if accompanied by other nephrotoxic events. Angiotensin II receptor(1) blockers (ARB) are thought to have fewer side-effects on renal perfusion and function. We examined the effects of valsartan (VAL) on kidney function as well as the contribution of the nitric oxide (NO) system in a rat model of ischaemic acute renal failure (ARF).

METHODS

ARF was induced by 40 min of clamping of both renal arteries in female Sprague-Dawley rats. Renal haemodynamic and tubular parameters were determined during post-ischaemic infusion of vehicle, VAL, VAL and the NO-synthase substrate L-arginine, and VAL together with inhibition of NO synthases (NOS) by L-NMMA.

RESULTS

Clamping induced acute renal failure with marked decreases in glomerular filtration rate (GFR) and renal plasma flow (RPF) accompanied by a rise in renal vascular resistance (RVR) and fractional sodium excretion. Valsartan caused a slight but significant improvement of GFR and RPF without full recovery of renal function and caused a lowering of RVR and tubular sodium loss. L-arginine-co-administration had no additive beneficial effect. Valsartan-induced changes were not significantly depressed by unspecific inhibition of NOS.

CONCLUSIONS

Inhibition of the angiotensin II-receptor(1) diminishes the deleterious effects of ischaemia and reperfusion on glomerular function and on the renal microcirculation. An involvement of the NO system could not be demonstrated.

Reversible renal impairment induced by treatment with the angiotensin II receptor antagonist candesartan in a patient with bilateral renal artery stenosis

BACKGROUND

It is well established that ACE-inhibitors should be avoided in patients with renal artery stenosis. In recent years it has also been recommended that caution should be demonstrated when angiotensin II blockers are used in the same type of patients but the evidence is based only on few cases.

RESULTS

We describe a case where use of the angiotensin II antagonist candesartan (Atacand) induced renal failure in a patient with bilateral renal artery stenosis. The course of the case is enlighted by results from sequential renography, selective renal vein catheterisation for measurement of renin, and angiographic findings.

CONCLUSIONS

In patients with renal artery stenosis the angiotensin II antagonist candesartan should be avoided.

Repeated transient anuria following losartan administration in a patient with a solitary kidney

We report the case of a 70-year-old hypertensive man with a solitary kidney and chronic renal insufficiency who developed two episodes of transient anuria after losartan administration. He was hospitalized for a myocardial infarction with pulmonary edema, treated with high-dose diuretics. Due to severe systolic dysfunction losartan was prescribed. Surprisingly, the first dose of 50 mg of losartan resulted in a sudden anuria, which lasted eight hours despite high-dose furosemide and amine infusion. One week later, by mistake, losartan was prescribed again and after the second dose of 50 mg, the patient developed a second episode of transient anuria lasting 10 hours. During these two episodes, his blood pressure diminished but no severe hypotension was noted. Ultimately, an arteriography showed a 70-80% renal artery stenosis. In this patient, renal artery stenosis combined with heart failure and diuretic therapy certainly resulted in a strong activation of the renin-angiotensin system (RAS). Under such conditions, angiotensin II receptor blockade by losartan probably induced a critical fall in glomerular filtration pressure. This case report highlights the fact that the angiotensin II receptor antagonist losartan can cause serious unexpected complications in patients with renovascular disease and should be used with extreme caution in this setting.

End-stage renal failure after irbesartan prescription in a diabetic patient with previously stable chronic renal insufficiency

We report the case of a 78-year-old hypertensive diabetic patient without evidence of renal artery stenosis who had moderate chronic renal insufficiency, which had been stable for several years under low-dose captopril therapy, and who rapidly developed acute renal failure when irbesartan was prescribed. Unfortunately the medication was not stopped promptly and the patient never recovered his basal renal function and had to undergo chronic hemodialysis. This observation emphasizes the importance of a careful monitoring of renal function in patients receiving angiotensin II receptor antagonists.

Angiotensin II receptor antagonists

Blockade of the renin-angiotensin system began as a way of studying the pathogenesis of cardiovascular disease with specific pharmacological probes. Oral activity, achieved by shortening the original peptide structures, transformed the probes into therapeutic agents, the angiotensin-converting enzyme (ACE) inhibitors. However, ACE is a non-specific target for blocking the renin-angiotensin enzymatic cascade. The availability of orally active drugs turned ACE inhibition into a therapeutic breakthrough but more specific blockade always seemed desirable. This goal has now been achieved with the orally active angiotensin II receptor antagonists; six are on the market and more are under development. This new class of drugs is equal in efficacy to ACE inhibitors, at least in hypertensive patients. Trials now underway will demonstrate whether angiotensin II receptor antagonists can prevent target-organ damage and reduce cardiovascular morbidity and mortality. If they do, these compounds might one day replace ACE inhibitors.

Renal artery stenosis as a cause of renal impairment: implications for treatment of hypertension and congestive heart failure

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Angiotensin II receptor antagonists and hypertension

Over recent years, a number of imidazole derivatives that specifically bind to the angiotensin II type 1 receptor, thereafter called sartans, have been developed and made available to the clinician. Whether targeting antihypertensive treatment with such a high specificity within the renin cascade may carry major clinical advantage over inhibiting angiotensin converting-enzyme remains to be demonstrated. In short-term studies, the efficacy of these drugs at reducing blood pressure was similar to that of established comparators, whereas overall side effect profile was comparable to that of placebo.

Practical considerations of the pharmacology of angiotensin receptor blockers

A review of the drug class of angiotensin receptor blockers (ARBs) as well as the ARBs currently available by prescription in the United States is presented. The importance of angiotensin II production by non-angiotensin-converting enzyme (non-ACE) pathways, particularly human chymase, is discussed. Emphasis is placed on the mechanism of action of ARBs and the different binding kinetics of these agents. Although all ARBs, as a group, block the AT1 receptor, they may differ in the pharmacological characteristics of their binding and be classified as either surmountable or insurmountable antagonists. Mechanisms of surmountable and insurmountable antagonism as well as possible benefits of these blocking characteristics are discussed in relation to the various ARBs. The cardiovascular effects of activation of the two main subtypes of angiotensin receptors (AT1 and AT2) are presented. In addition to their treatment of hypertension, ACE inhibitors are recognized as being effective in the management of heart failure, left ventricular hypertrophy, recurrent myocardial infarctions, and renal disease. ARBs are currently indicated only for the treatment of hypertension; however, in vitro and in vivo pharmacological studies as well as preliminary clinical data suggest that ARBs, like ACE inhibitors, may also provide effective protection against end-organ damage in these conditions.

A case of renal artery stenosis after transplantation: can losartan be more accurate than captopril renography?

Hypertension is a common complication observed after renal transplantation. If the hypertension is of renovascular origin, transluminal angioplasty or surgery of the renal artery stenosis can lead help cure the hypertension. The blood pressure of a 31-year-old man who underwent renal transplantation 2 years earlier gradually increased. Arteriography showed stenosis (>80%) in the two branches of the renal artery. To help confirm the presence of renovascular hypertension, captopril renography was performed but showed no significant changes compared with baseline renography. Renography was performed again after losartan administration and showed impaired renal function. In this case, losartan renography was more useful than captopril in suggesting renovascular hypertension.

Losartan as an alternative to ACE inhibitors in patients with renal dysfunction

Losartan-induced acute renal failure may occur in patients sensitive to reduced renal plasma flow. Such patients include those with bilateral renal artery stenosis, severe congestive heart failure, and severe sodium and volume depletion because their renal function is often angiotensin-dependent. Theoretically, both ACE inhibitors and losartan could adversely affect renal function in such sensitive patients. The ELITE trial showed a 10.5% incidence of losartan-induced renal dysfunction in elderly patients with congestive heart failure with no known underlying renal dysfunction, an incidence identical to that for captopril. A review of the literature revealed no controlled trials that specifically address whether losartan can be used as an alternative in patients in whom renal dysfunction associated with losartan have been published and an additional case report was identified from a local adverse drug reaction monitoring program. There were two cases of patients who developed renal dysfunction while receiving ACE inhibitors and then losartan. We found only one published case in which losartan was used without deterioration in renal function in patients who developed renal dysfunction while taking an ACE inhibitor, although underreporting of such cases would be expected. There was one case of renal dysfunction with losartan after a lack of renal dysfunction while the patient was taking an ACE inhibitor. The remaining three reports are of patients who developed renal dysfunction while taking losartan with no antecedent ACE inhibitor use. All case reports describe renal deterioration that was reversible upon discontinuation of the inciting agent, whether an ACE inhibitor or losartan. All but two patients (personal communication, Barbara Cadario) had underlying renal pathology. Although there is a paucity of published literature and the clinical experience of some may suggest otherwise, there is currently no evidence (with the exception of 1 case report) to suggest that losartan is any better tolerated than ACE inhibitors from the standpoint of renal toxicity. Available evidence suggests that this is equally true in patients with and without underlying renal dysfunction. Furthermore, case reports suggest that, as with ACE inhibitors, losartan should be avoided in patients with bilateral renal artery stenosis and in patients with unilateral renal artery stenosis in a solitary kidney. In patients with underlying renal dysfunction, regardless of whether they tolerate ACE inhibitors, losartan may be used if deemed necessary. Renal function should be monitored and losartan should be stopped if evidence of renal dysfunction becomes apparent, since several case reports and a randomized trial suggest that losartan may cause the same negative renal effects as ACE inhibitors.