dihydropyridines and Renal-Insufficiency

Manidipine is a lipophilic, third-generation dihydropyridine calcium channel antagonist with a high degree of selectivity for the vasculature, thereby inducing marked peripheral vasodilation with negligible cardiodepression. In addition, manidipine does not significantly affect norepinephrine levels, suggesting a lack of sympathetic activation. It has a gradual onset of action and a long duration of action enabling once daily administration. Furthermore, manidipine dilates both the efferent and the afferent renal arterioles and appears to have beneficial renal effects unrelated to its antihypertensive effect. Once-daily oral manidipine is an effective and generally well tolerated antihypertensive agent for younger and elderly adult patients with mild-to-moderate hypertension. In particular, in a large double-blind trial, the incidence of ankle oedema was significantly lower in manidipine than in amlodipine recipients. Manidipine is also effective in hypertensive patients with comorbidities, such as type 2 diabetes mellitus and/or renal impairment, and appears to improve insulin sensitivity without affecting metabolic function. Thus, manidipine represents a first-line treatment option for patients with essential mild-to-moderate hypertension.

Topics: Adult; Aged; Antihypertensive Agents; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Dihydropyridines; Humans; Hypertension; Middle Aged; Nitrobenzenes; Piperazines; Renal Insufficiency

There are few studies on the use of dihydropyridine calcium antagonists in hypertensive patients with moderate renal insufficiency. We undertook an open study on the effects on renal function, albumin excretion and blood pressure of the slow-onset, long-acting dihydropyridine calcium antagonist, lacidipine, in 14 patients with stable, chronic renal insufficiency (mean assessed GFR 0.78 ml/s, range 0.50-1.17 ml/s) and moderate hypertension. Following a 2 week washout phase, lacidipine was administered for 24 weeks in a dose of 2 mg/day with the dose being titrated at 2 weekly intervals to a maximum of 6 mg/day in order to achieve adequate blood pressure control. Frusemide was introduced if blood pressure was not controlled on the maximum lacidipine dose. Blood pressure, creatinine clearance, 24 h urinary albumin excretion and plasma creatinine and albumin concentrations were measured at regular intervals throughout the study. Isotopic GFR was determined at the end of the washout period and at week 24. Lacidipine was not very effective in controlling blood pressure and had an adverse effect on renal function. In 3 patients with an incipient nephrotic syndrome this necessitated withdrawal from the study. Mean GFR of the 10 patients who completed the study decreased from 0.69 ml/s/1.73 m2 at baseline to 0.56 ml/s/1.73 m2 at week 24 (p = 0.006) with a decline in GFR being observed in 9 of these patients. The decrease in GFR was greatest in patients with poorly controlled blood pressure. An insignificant increase in mean urinary albumin excretion occurred during the study with this increase being observed only in patients with albuminuria > 1 g/24 h at baseline. These findings indicated that systemic hypertension altered glomerular hemodynamics and that the vasodilatation of pre-glomerular vessels which followed introduction of the calcium antagonist may have exacerbated this situation. The withdrawal of an angiotensin converting enzyme inhibitor during the washout period may have contributed to these changes. We suggest that renal function should be monitored closely in patients with renal insufficiency when a calcium antagonist is being used to control blood pressure, particularly in those with either marginal blood pressure control, significant albuminuria or an incipient nephrotic syndrome.

Topics: Adult; Aged; Albuminuria; Antihypertensive Agents; Blood Pressure; Calcium Channel Blockers; Dihydropyridines; Female; Furosemide; Glomerular Filtration Rate; Humans; Hypertension; Kidney; Male; Middle Aged; Renal Insufficiency; Serum Albumin

A growing body of evidence indicates that renal tissue injuries are reversible. We investigated whether dietary salt reduction with the combination therapy of angiotensin II type 1 receptor blocker (ARB) plus calcium channel blocker (CCB) reverses renal tissue injury in Dahl salt-sensitive (DSS) hypertensive rats. DSS rats were fed a high-salt diet (HS; 4% NaCl) for 4 weeks. Then, DSS rats were given one of the following for 10 weeks: HS diet; normal-salt diet (NS; 0.5% NaCl), NS + an ARB (olmesartan, 10 mg/kg/day), NS + a CCB (azelnidipine, 3 mg/kg/day), NS + olmesartan + azelnidipine or NS + hydralazine (50 mg/kg/day). Four weeks of treatment with HS diet induced hypertension, proteinuria, glomerular sclerosis and hypertrophy, glomerular podocyte injury, and tubulointerstitial fibrosis in DSS rats. A continued HS diet progressed hypertension, proteinuria and renal tissue injury, which was associated with inflammatory cell infiltration and increased proinflammatory cytokine mRNA levels, NADPH oxidase activity and NADPH oxidase-dependent superoxide production in the kidney. In contrast, switching to NS halted the progression of hypertension, renal glomerular and tubular injuries. Dietary salt reduction with ARB or with CCB treatment further reduced blood pressure and partially reversed renal tissues injury. Furthermore, dietary salt reduction with the combination of ARB plus CCB elicited a strong recovery from HS-induced renal tissue injury including the attenuation of inflammation and oxidative stress. These data support the hypothesis that dietary salt reduction with combination therapy of an ARB plus CCB restores glomerular and tubulointerstitial injury in DSS rats.

Topics: Angiotensin Receptor Antagonists; Animals; Azetidinecarboxylic Acid; Blood Pressure; Calcium Channel Blockers; Combined Modality Therapy; Cytokines; Diet, Sodium-Restricted; Dihydropyridines; Drug Evaluation, Preclinical; Gene Expression; Gene Expression Regulation; Hypertension; Imidazoles; Kidney Glomerulus; Male; NADPH Oxidases; Rats, Inbred Dahl; Receptors, Mineralocorticoid; Renal Insufficiency; Tetrazoles