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Query: UMLS:C0085580 (essential hypertension)
 14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Renal vascular resistance is increased in essential hypertension, with a consequent reduction in renal plasma flow together with a normal or slightly reduced glomerular filtration rate. Non-specific vasodilators may exacerbate this effect while loop diuretics, beta-blockers, angiotensin converting enzyme inhibitors and calcium antagonists may increase these renal hemodynamic parameters. We studied the effect of lacidipine, a new long-lasting calcium antagonist, on renal hemodynamics in 11 essential hypertensives. Lacidipine (4 mg once a day) acutely increased renal plasma flow without affecting the glomerular filtration rate. A transient, but non-significant, diuresis and natriuresis occurred. After 4 weeks of lacidipine treatment, all the parameters of renal function returned to basal levels. These results suggest that the well known renal effects of calcium antagonists are, at least in part, related to the onset of the antihypertensive effect being more pronounced with compounds such as nifedipine which have a rapid-onset, blood pressure-lowering effect.
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PMID:The effects of antihypertensive therapy on renal function. 168 83

The effects of calcium antagonists in reducing blood pressure at rest and during exercise were examined in patients with mild-to-moderate essential hypertension. The haemodynamic effects of calcium antagonists were evaluated at rest and during exercise. We also examined 10 patients with mild-to-moderate essential hypertension taking lacidipine, a new dihydropyridine calcium antagonist (4 mg once a day, at 0700 h). Compared with placebo, lacidipine induced significant mean reductions in 24-h blood pressure (P less than 0.001 for systolic blood pressure; P less than 0.002 for diastolic blood pressure). After 24 h, the blood pressure reductions were still significant (P less than 0.02 for systolic blood pressure; P less than 0.04 for diastolic blood pressure). The heart rate did not change. During dynamic exercise, blood pressure at maximal effort was reduced (P less than 0.01 for systolic and diastolic blood pressure) and the external workload reached at the anaerobic threshold was significantly increased (P less than 0.001), but not at maximum effort. Ventilation and tidal volume were similar at both the anaerobic threshold and peak exercise, while oxygen uptake and carbon dioxide production were increased at the anaerobic threshold (P less than 0.02 for carbon dioxide production) but were similar at peak exercise.
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PMID:Exercise-induced modifications in cardiorespiratory parameters of hypertensive patients treated with calcium antagonists. 168 84

In a double-blind, double-dummy, placebo-controlled crossover design, the renal hemodynamic and tubular effects of 2-month specific vasodilation with a converting enzyme inhibitor (enalapril, 40 mg once daily) was compared with that of a calcium antagonist (verapamil slow release, 240 mg twice daily) in 15 patients with established essential hypertension. Enalapril and verapamil treatment induced a 9% reduction in mean blood pressure (BP). Heart rate (HR) was similar after placebo (66 beats/min), enalapril (63 beats/min), and verapamil (63 beats/min). Plasma norepinephrine (P-NE) was unaltered after enalapril and verapamil as compared with placebo (0.92, 0.88, and 1.33 nM, respectively). Plasma angiotensin II and aldosterone decreased and plasma renin activity (PRA) increased after enalapril but were unaltered after verapamil. Glomerular filtration rate (51Cr-EDTA) was not altered by either enalapril or verapamil, whereas renal blood flow (125I-hippurate) was reduced 9% by verapamil. Renal vascular resistance (RVR) was unchanged after enalapril as well as verapamil. Fractional excretion of electrolytes and diuresis were unaltered and body weight was similar after enalapril, verapamil, and placebo (81.0, 82.5, and 80.2 kg, respectively). Long-term treatment with enalapril and verapamil had a comparable antihypertensive effect. Neither enalapril nor verapamil appeared to induce reflex activation of the sympathetic nervous system. Renal hemodynamic and tubular function was well preserved with both drugs without signs of sodium and water retention.
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PMID:Renal and endocrine effects of long-term converting enzyme inhibition as compared with calcium antagonism in essential hypertension. 169 57

Felodipine, a dihydropyridine calcium antagonist, was used to treat eight patients with severe uncontrolled hypertension: five had essential hypertension, two had renovascular disease, and one chronic pyelonephritis. Mean blood pressure (BP) was 221 +/- 14/120 +/- 4 mm Hg despite treatment with three or more antihypertensive drugs. All patients experienced an immediate and pronounced lowering of BP after adding felodipine, which persisted during long-term treatment in combination with previous medication except for vasodilating drugs. In all cases, an increase in glomerular filtration rate (51Cr-EDTA clearance) after 6 and 12 months of felodipine treatment was seen (59 +/- 10 to 63 +/- 7 and 70 +/- 6 ml/min, respectively, p less than 0.05). Renal plasma flow (PAH clearance) exhibited only a slight increase (315 +/- 68 to 340 +/- 63 and 314 +/- 69 ml/min), giving a nonsignificant rise in filtration fraction (18 +/- 1 to 21 +/- 1 and 20 +/- 1%, respectively). It is concluded that felodipine decreases BP dramatically in patients with previously refractory hypertension and that the drug causes an improved renal function in these patients.
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PMID:Long-term effects of felodipine on blood pressure and renal hemodynamics in severe hypertension. 169 10

Felodipine is a new calcium antagonist that was developed aiming particularly at reduction in vascular resistance-without any decrease in heart pump function. Studies in animals have demonstrated that felodipine given intravenously induces an acute fall in total peripheral resistance and blood pressure (BP), associated with acute reflex tachycardia and an increase in cardiac output (CO). During chronic treatment, the reflex tachycardia is abolished, while resistance and BP remain reduced. Acute vasodilatation has been demonstrated in the heart, kidneys, intestines, and skeletal muscles. Increased blood flow has also been demonstrated in the coronary arteries. Acute studies in humans with essential hypertension have demonstrated similar effects to what has been observed in the spontaneously hypertensive rat (SHR): a marked fall in total peripheral resistance and BP-associated with reflex tachycardia and increased CO. There is also an increase in coronary renal, and forearm blood flow. Catheterization studies have indicated that felodipine also dilates large coronary arteries. During chronic treatment in 16 males with initial diastolic BP of 100-120 mm Hg, felodipine reduced total peripheral resistance approximately 15% at rest and during exercise without significant changes in cardiac index (CI), heart rate (HR), and stroke volume (SV). As in animals, no reflex tachycardia is seen during chronic treatment. It is concluded that felodipine reduces BP in hypertensive animals and humans because of the marked effect on total peripheral resistance. CO is not reduced either at rest or during exercise. During chronic treatment, reflex tachycardia is abolished.
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PMID:Hemodynamic effects of felodipine in hypertension: a review. 169 23

Calcium antagonists demonstrate a close relationship between plasma drug level and effect on blood pressure (BP). Thus, the intensity and duration of action can be influenced by dose and disposition. Felodipine has a dose-related effect on diastolic BP whether given alone or with a beta-blocker. The latter combination reduces adverse effects and improves tolerability, particularly at higher (20 mg/day) doses of felodipine. Felodipine 5 or 10 mg/day in an extended release formulation could be predicted to lower BP throughout a 24-h period. The results of formal prospective clinical trials confirm the predictions and indicate that felodipine can be used as a once-daily agent in essential hypertension.
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PMID:Dose-plasma concentration--effect relationship of felodipine in essential hypertension: a review. 169 28

Seventeen middle-aged males with sustained essential hypertension (WHO stage II) and diastolic blood pressures (BP) exceeding 100 mm Hg during a placebo run-in period completed a trial to assess the hemodynamic effects of isradipine, a new dihydropyridine calcium antagonist. The study was double-blind and placebo-controlled with a crossover design. Brachial artery compliance was assessed as the ratio of stroke volumes and simultaneous pulse pressure. During therapy with isradipine (all patients received 7.5 mg b.i.d.), highly significant reductions in supine systolic BP [from 184 +/- 16 to 162 +/- 20 mm Hg (mean +/- S.D.)] and diastolic BP (from 96 +/- 8 to 83 +/- 8 mm Hg) were observed. Heart rate was unchanged (69 +/- 3 vs. 73 +/- 2 beats/min) during chronic therapy. Total peripheral resistance was significantly reduced (from 24.8 +/- 9 to 17.4 +/- 5 units) while cardiac output was unchanged (6.0 +/- 1.9 vs. 7.2 +/- 1.8 L/min). Stroke volume was unchanged (92 +/- 25 vs. 100 +/- 25 ml/beat), and a significant (p less than 0.05) increase in brachial artery compliance (from 1.05 +/- 0.25 to 1.26 +/- 0.35 ml/mm Hg) was observed.
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PMID:Central hemodynamics and brachial artery compliance during therapy with isradipine, a new calcium antagonist. 169 12

Lipid profiles were determined in 56 elderly patients with benign essential hypertension during an open-label 1-year study of the safety and efficacy of isradipine, a new calcium antagonist, in controlling blood pressure. Patients with diastolic blood pressures between 96 and 115 mm Hg were titrated with isradipine (mean dose of 11 mg/day) to reduce blood pressure to less than 90 mm Hg. Ten of these patients received concomitant hydrochlorothiazide (HCTZ) 50 mg/day for additional control. Sera were analyzed using standard methods at the end of a 2- to 4-week washout period, and at the end of Months 6 and 12, for total cholesterol (CHOL) and HDL- and LDL-cholesterol. Changes in lipid values (mg/dl) from baseline to 12 months with isradipine alone (n = 38) were as follows: CHOL, -7.5; HDL, +3.9 (p less than 0.05); LDL, -6.2; CHOL/HDL, -0.6 (p less than 0.05). For patients receiving concomitant HCTZ (n = 9), the changes were as follows: CHOL, -4.9; HDL, +3.4; LDL, -16.8; CHOL/HDL, -0.4. In conclusion, isradipine alone was associated with significant improvements in HDL cholesterol and total CHOL/HDL ratio. Lipid profiles of patients receiving isradipine and HCTZ were minimally affected. Favorable lipid changes with isradipine suggest that it may have advantages in the treatment of hypertensive patients.
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PMID:Long-term lipid profiles with isradipine and hydrochlorothiazide treatment in elderly hypertensive patients. 169 13

Torasemide (torsemide) is a high-ceiling loop diuretic which acts on the thick ascending limb of the loop of Henle to promote rapid and marked excretion of water, sodium and chloride. Like furosemide (frusemide), its major site of action is from the luminal side of the cell. Torasemide is at least twice as potent as furosemide on a weight-for-weight basis, produces equivalent diuresis and natriuresis at lower urinary concentrations and has a longer duration of action, allowing once-daily administration without the paradoxical antidiuresis seen with furosemide. Torasemide also appears to promote excretion of potassium and calcium to a lesser extent than furosemide. In trials of up to 48 weeks' duration in patients with mild to moderate essential hypertension, torasemide, administered as a single daily dose, has been shown to achieve adequate blood pressure control reaching steady-state within 8 to 12 weeks. Those patients not responding initially have generally responded to a doubling of the dose. Comparative trials of up to 6 months show torasemide is as effective as indapamide, hydrochlorothiazide or a combination of triamterene/hydrochlorothiazide in maintaining control of blood pressure. Torasemide has also been used successfully to treat oedematous states associated with chronic congestive heart failure, renal disease and hepatic cirrhosis. In short term trials control of blood pressure, bodyweight and residual oedema has been sustained. Torasemide appears to be a useful alternative to furosemide in these patients, providing potent and long-lasting diuresis while being relatively potassium and calcium sparing. In clinical trials to date torasemide has been well tolerated with adverse effects of a mild, transient nature reported by only small numbers of patients. Changes in biochemical parameters have been common, including decreases in plasma sodium and potassium levels and increases in plasma creatinine and uric acid levels. These changes are typical of loop diuretics. No changes were clinically significant nor were clinically relevant changes noted in glucose metabolism, cholesterol or triglyceride levels or in haematological values. Thus, torasemide is an interesting new loop diuretic with potential use in the treatment of mild to moderate essential hypertension and of oedematous states in which diuretic therapy is warranted. Preliminary studies suggest it to be as efficacious as other diuretics in common use and to have some advantage over furosemide in duration of action and in effects on potassium and calcium. However, further long term trials in larger groups of patients are needed to delineate the place of torasemide in therapy fully, both as a single agent and in combination with other currently accepted drug regimens.
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PMID:Torasemide. A review of its pharmacological properties and therapeutic potential. 170 90

The arterial vasodilator properties of the calcium antagonist diltiazem were investigated by measurement of changes of forearm blood flow during brachial artery infusions of eight dosages of diltiazem in eight hypertensive patients. Forearm blood flow increased and calculated forearm vascular resistance decreased dose-dependently (maximum decrease of 83.5 +/- 8.6%). When comparing the effects of calcium influx inhibition by diltiazem with stimulation of the vascular cyclic guanosine monophosphate (GMP) system by sodium nitroprusside, the vasodilation by diltiazem was approximately 1.6 times greater, attesting to its potent arterial vasodilator activity. The clinical efficacy and feasibility of diltiazem monotherapy was evaluated in 40 patients with mild to moderate essential hypertension treated with a slow-release formulation of diltiazem, 90 mg twice daily over 8 weeks, and in a subgroup of 21 patients with two tablets of 90 mg once daily in the morning over a period of 2 weeks. Blood pressure was lowered significantly and to a similar extent by either twice- or once-daily administration of diltiazem. This effect was maintained during open long-term therapy over a mean of 11 months. Heart rate and body weight did not change. Thus, the vasodilator properties of diltiazem can be utilized for effective long-term treatment of hypertension. The possibility of once-daily dosing may prove useful with respect to drug compliance in the long-term treatment of a generally asymptomatic disease such as hypertension.
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PMID:Arterial vasodilator and antihypertensive effects of diltiazem. 170 18


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