Ambulatory blood pressure parameters after canrenone addition to existing treatment regimens with maximum tolerated dose of angiotensin-converting enzyme inhibitors/angiotensin II type 1 receptor blockers plus hydrochlorothiazide in uncontrolled hypertensive patients.

BACKGROUND: Blockade of the renin-angiotensin-aldosterone system is a cornerstone in cardiovascular disease prevention and hypertension treatment. The relevance of ambulatory blood pressure monitoring (ABPM) has been widely confirmed for both increasing the accuracy of blood pressure (BP) measurements, particularly in pharmacological trials, and focusing on 24 h BP prognostic parameters. The aim of this study was to assess the effects of canrenone addition on ambulatory BP in uncontrolled hypertensive patients already treated with the highest tolerated dose of angiotensin-converting enzyme (ACE) inhibitors or angiotensin II type 1 receptor (AT1R) antagonists plus hydrochlorothiazide (HCT). METHODS: ABPM was performed at baseline and after 3 months of combination therapy in 158 outpatients with stage 1 or 2 hypertension who were randomized to add canrenone (50 or 100 mg) to the pre-existing therapy with ACE inhibitors or AT1R antagonists plus HCT. Twenty-four-hour systolic and diastolic BPs were considered normalized when the values were <130 and <80 mmHg, respectively. RESULTS: The addition of canrenone was associated with a reduction in systolic and diastolic BPs (24 h and daytime and nighttime; P<0.001), mean arterial pressures (P<0.001), and pulse pressures (P<0.01). The Δ 24 h systolic/diastolic BPs were -13.5±11.2/-8±8 mmHg and -16.1±13.5/-11.2±8.3 mmHg (50 and 100 mg/day, respectively). In the 50 mg arm, the 24 h systolic and diastolic BPs were normalized in 67.5% and 74% of the patients, respectively, and in 61.6% and 68.5% of the patients in the 100 mg arm, respectively (P<0.05; P= not significant for 50 vs 100 mg). The percentage of patients whose nocturnal decrease was >10% with respect to diurnal values did not change during combination therapy. CONCLUSION: Canrenone addition to ACE inhibitors or AT1R antagonists plus HCT was associated with a significant reduction of 24 h BP and to an increased number of patients meeting 24 h ABPM targets in a clinical setting of uncontrolled stage 1 or 2 hypertension.

Efficacy and safety of two dosages of canrenone as add-on therapy in hypertensive patients taking ace-inhibitors or angiotensin II receptor blockers and hydrochlorothiazide at maximum dosage in a randomized clinical trial: The ESCAPE-IT trial.

AIM: To evaluate the effects of canrenone as add-on therapy in patients already treated with angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin II receptor blockers (ARBs) and hydrochlorothiazide at the maximum dosage (25 mg/d). METHOD: In this randomized, open-label, controlled trial, we enrolled 175 Caucasian patients with essential hypertension not well controlled by concomitant ACE-I or ARBs and hydrochlorothiazide. At baseline, 87 patients (57 males and 30 females) were randomized to add canrenone 50 mg, and 88 (56 males and 32 females) patients to canrenone 100 mg, once a day, for 3 months. At baseline and after 3 months, we evaluated blood pressure (BP), pulse pressure (PP), heart rate (HR), fasting plasma glucose (FPG), homeostasis model assessment insulin (HOMA Index), lipid profile, electrolytes, uric acid, estimated glomerular filtration rate (eGFR), plasma urea, aldosterone, B-type natriuretic peptide (BNP), and galectin-3. RESULTS: Blood pressure decreased with both dosages of canrenone, with a better effect with canrenone 100 mg (-20.26 vs -23.68 mm Hg for SBP, and -10.58 vs -12.38 mm Hg for DBP), without a clinically relevant increase in potassium levels. We did not observe any differences regarding FPG or HOMA Index, nor of lipid profile, with the exception of triglycerides, which increased compared to baseline with canrenone 50 mg (+0.25 vs +0.34 mEq/L). Creatinine slightly increased with canrenone 100 mg (+0.02 vs +0.05 mg/dL), although no variations of eGFR were observed in neither groups. There was an increase in aldosterone levels with canrenone 50 mg. No changes in BNP or galectin-3 were recorded. CONCLUSION: Both canrenone dosages gave a decrease in blood pressure, with a better effect with the higher dose, with only a slight increase in potassium and creatinine levels, which were not clinically relevant. Clinical Trials Registration Eudract number: 2010-023606-13; ClinicalTrials.gov NCT02687178.

The negative inotropic action of canrenone is mediated by L-type calcium current blockade and reduced intracellular calcium transients.

BACKGROUND AND PURPOSE: Adding spironolactone to standard therapy in heart failure reduces morbidity and mortality, but the underlying mechanisms are not fully understood. We analysed the effect of canrenone, the major active metabolite of spironolactone, on myocardial contractility and intracellular calcium homeostasis. EXPERIMENTAL APPROACH: Left ventricular papillary muscles and cardiomyocytes were isolated from male Wistar rats. Contractility of papillary muscles was assessed with force transducers, Ca(2+) transients by fluorescence and Ca(2+) fluxes by electrophysiological techniques. KEY RESULTS: Canrenone (300-600 micromol L(-1)) reduced developed tension, maximum rate of tension increase and maximum rate of tension decay of papillary muscles. In cardiomyocytes, canrenone (50 micromol L(-1)) reduced cell shortening and L-type Ca(2+) channel current, whereas steady-state activation and inactivation, and reactivation curves were unchanged. Canrenone also decreased the Ca(2+) content of the sarcoplasmic reticulum, intracellular Ca(2+) transient amplitude and intracellular diastolic Ca(2+) concentration. However, the time course of [Ca(2+)](i) decline during transients evoked by caffeine was not affected by canrenone. CONCLUSION AND IMPLICATIONS: Canrenone reduced L-type Ca(2+) channel current, amplitude of intracellular Ca(2+) transients and Ca(2+) content of sarcoplasmic reticulum in cardiomyocytes. These changes are likely to underlie the negative inotropic effect of canrenone.

[Anti-angiogenic effects of aldosterone antagonists in the fibrin chamber in rats]. / Effets anti-angiogéniques d'antagonistes de l'aldostérone dans la chambre de fibrine chez le rat.

Spironolactone, a diuretic antagonist of aldosterone has an unexplained side effect of amenorrhea which could be due to an angiogenesis inhibition. In this study we compared the effects of spironolactone, canrenone an active metabolite of spironolactone and eplerenone a more selective mineralocorticoid antagonist in rats implanted with a fibrin gel chamber. Perforated plexiglass chambers filled with rat fibrin, spironolactone (50 microM), canrenone (100 microM), eplerenone (500 microM), DMSO (0.05%) and control were implanted into the dorsal subcutaneous space of wistar rats. After 14 days of implantation, an invasion of the fibrin gel chamber by neovascularised buds had occurred through the holes. The number of vessels in the central field and in two or three peripheral fields covering the surface of the bud, were measured for each drug tested and compared to the control. In spironolactone treated chambers, the numbers of peripheral and central vessels were significantly reduced compared to control (p < 0.001). Canrenone, eplerenone and DMSO did not reduce the number of vessels (m +/- ESM, ANOVA followed by Newman-Keuls test). Spironolactone but not canrenone, nor eplerenone inhibited vessels formation in vivo. This antiangiogenic activity appeared to be not related to the antimineralocorticoid effect of spironolactone.

Digoxin assays: frequent, substantial, and potentially dangerous interference by spironolactone, canrenone, and other steroids.

BACKGROUND: A case of digoxin toxicity resulted from falsely low values with the MEIA II assay for digoxin (AxSYM; Abbott). The low results were caused by negative interference from canrenone and spironolactone, the latter of which has recently been advocated for the treatment of severe heart failure. Analytical interference from spironolactone has been reported, but little information is available for this effect with newer digoxin assays. METHODS: We examined nine assays (AxSYM, IMx, TDx, Emit, Dimension, aca, TinaQuant, Elecsys, and Vitros for interference by spironolactone, canrenone, and three metabolites. Additionally, all routine digoxin measurements (AxSYM) over a period of 16.5 months (n = 3089) were monitored for interference. RESULTS: Suppression of the expected values by canrenone (3125 microg/L) was observed for the AxSYM (42% of expected value), IMx (51%), and Dimension (78%) assays. A positive bias was observed for the aca (0.7 microg/L), the TDx (0.62 microg/L), and the Elecsys (>0.58 microg/L). Twenty-five of 669 routinely monitored patients had falsely low results. Nineteen of these had potentially toxic concentrations of digoxin (Emit; >2.0 microg/L), although the AxSYM assay indicated therapeutic or less severe toxic concentrations (Delta(max) = 7.1 microg/L). Except for two unresolved cases, this was attributable to spironolactone, canrenone, hydrocortisone, or prednisolone. Standard doses of spironolactone (up to 50 mg/day) in patients with heart failure displayed inhibition <11%. CONCLUSIONS: The frequency and magnitude of the false-negative results particularly compromise the use of both microparticle enzyme immunoassays. Not only may toxic concentrations remain unidentified, but intoxication could occur should dosage be increased because of falsely low results. With 11 million digoxin tests/year ordered in the US, conceivably many patients could be adversely affected.

Effects of canrenone on blood pressure in rats with reduced renal mass.

Canrenone, a metabolic product of spironolactone, which competes with ouabain for binding to Na-K-ATPase at the digitalis receptor site and by itself inhibits Na-K-ATPase, was administered intramuscularly to reduced renal mass-saline drinking hypertensive and reduced renal mass-distilled water drinking normotensive rats for 8 days. Reduced renal mass-saline hypertension in the rat, is a low renin, volume expanded form of hypertension. Rats with this type of hypertension have been shown to have depressed arterial Na-K pump activity and increased Na-K pump inhibitory activity in their plasma. Canrenone treatment caused a progressive decrease in blood pressure in the hypertensive rats and this was associated with normalization of Na-K pump activity in arteries. Water and salt intake and excretion did not change. On the other hand, canrenone progressively increased blood pressure in the normotensive rats and this was associated with positive inotropy in isolated papillary muscles. These findings suggest that the depressed pump activity and the pump inhibitor play a role in reduced renal mass-saline hypertension in the rat and that the rise in blood pressure in the normotensive rats probably reflects canrenone's ability, by itself, to inhibit Na-K-ATPase.

[Studies on the bioequivalence of canrenone using pharmacokinetic data and clinical effects]. / Untersuchungen zur Bioäquivalenz von Canrenon mittels pharmakokinetischer Daten und klinischem Effekt.

Canrenon, an active metabolite of spironolactone, and the combination of Canrenon with hydrochlorothiazide (HCT) were examined on patients with essential hypertension, cardial oedemas and oedemas of different origin, and than compared to a product available on the market. A correlation of the clinical effect (e.g. systolic blood pressure) with the morning steady state-data (blood values of Canrenon and HCT) has been achieved. The new preparations showed a good resorption in the gastro-intestinal tract. For an equivalent clinical effect, less Canrenon substance has been needed. A therapeutically satisfactory result has been reached with the administered dosage of both Canrenon and the comparison group. In the combination the higher dosage level should be chosen.

Pharmacokinetics of canrenone after oral administration of spironolactone and intravenous injection of canrenoate-K in healthy man.

Five healthy male volunteers received canrenoate-K 200 mg (Sincomen pro injectione) by intravenous injection and one week later spironolactone 200 mg (Sincomen-100) orally. Plasma levels and urinary excretion of unchanged canrenone were determined up to 24 h by a specific HPLC method. Following intravenous administration, the maximum plasma level of 2066 +/- 876 ng/ml was found after 29 +/- 15 min and thereafter the concentration declined with a half-life of 3.7 +/- 1.2 h. Total clearance was 4.2 +/- 1.7 ml/min . kg. After oral ingestion, the maximum concentration of 177 +/- 33 ng/ml was observed at 4.4 +/- 0.9 h. The absolute bioavailability of canrenone was 25 +/- 9%. Within 24 h, respectively 0.4 and 0.6 mg, canrenone were excreted by the kidney after intravenous and oral administration. The half-life of elimination was 4.9 +/- 1.8 h (i.v.) and 3.9 +/- 1.2 h (p.o.).

[Membrane activity of canrenone in the normotensive subject: evaluation and significance]. / L'activité membranaire de la canrénone chez le sujet normotendu : évaluation et signification.

Canrenone (100 mg per day) was given to ten young normotensive subjects during seven days. Plasma--K+ and erythrocytes--K+ (p less than 0,05), diuresis (+ 52%) and natriuresis (+ 70%) increased significantly during this time. Comparison between cations fluxes in erythrocytes before and after giving the drug showed an action on the membranal Na+ - K+ pump. This action site would complete well known anti-aldosterone properties.

Aldosterone antagonism studies in the rhesus monkey.

Renal studies in femal rhesus monkeys indicated that 10 micron g was an optimum i.m. sodium-retaining dose of aldosterone. Aldosterone was injected i.m. at dosages of 2.5, 5, 10 and 20 micron g/animal. The 10-micron g dose induced about a 50% reduction in sodium excretion (from 3.7 to 1.7 mEq/6 hr) and was selected as the standard dose for antagonism studies. K excretion and urine volume remained unchanged. Subsequently, the oral antialdosterone activities of spironolactone and canrenone, a delta6 metabolite, were assessed at dosages of 1, 4 and 8 mg/kg. Dose-related increases in the aldosterone-depressed urinary Na/k ratio occurred primarily as a consequence of enhanced sodium excretion. Canrenone possessed antialdosterone potency equal to that of spironolactone. In the absence of exogenous aldosterone, spironolactone (16 mg/kg) was essentially devoid of diuretic activity whereas hydrochlorothiazide (1 mg/kg) induced marked increases in Na (256%) and K (105%) excretion and urine volume (109%).

Application of a simple fluorometric method on absorption of canrenone.

The absorption of canrenone, the major metabolite of spironolactone, was studied by a simple fluorometric method in 30 healthy subjects. Two different pharmaceutical formulations were compared on absorption, and only a negligible difference was found between the micronized and balled-milled form. Canrenone in both formulations was well absorbed, whereas spironolactone absorption was slower. Mattingly's fluorometric assay proved to be a simple method to evaluate the absorption of canrenone.