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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glomerular hyperfiltration and hypertension induced by extensive loss of renal parenchyma are suspected to accelerate progression of renal failure. Amino acid infusion or protein ingestion also modify renal hemodynamics and increase glomerular filtration rate (GFR). This phenomenon was used to study the influence of two commonly used antihypertensive agents, captopril and nifedipine, on renal hemodynamics at rest and during glomerular hyperfiltration. Thirteen healthy volunteers were studied on three separate days (days A, B, and C) in random sequence: inulin and p-amino hippurate (PAH) clearance were measured first under glucose infusion and afterwards under stimulation by amino acid infusion (0.35 mmol/kg/min; 4 mg/kg/min). Day A served as a control, where no medication was given. On day B, 10 mg nifedipine, and on day C, 25 mg captopril, were administered orally before study. Without premedication (= day A, control) GFR increased from 108.0 +/- 6.9 mL/min (SEM) to 131.7 +/- 7.0 mL/min (P less than 0.05). On day B (nifedipine), GFR before stimulation by amino acids was already elevated to 121.8 +/- 4.2 mL/min (P less than 0.05 compared with day A) and increased to 132.6 +/- 6.3 mL/min with infusion of amino acids, thus to the same range as on day A without medication. On day C, after captopril, GFR did not increase with infusion of amino acids (from 112.5 +/- 7.2 to 117.3 +/- 6.3 mL/min). Our results indicate the calcium channel antagonist nifedipine and the angiotensin-converting enzyme (ACE) inhibitor captopril differ in their effect on intrarenal hemodynamic parameters. Nifedipine induces hyperfiltration at rest and allows maximal hyperfiltration to develop under amino acid infusion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of nifedipine and captopril on glomerular hyperfiltration in normotensive man. 149 65

Prevalence studies suggest that hypertension is present in more than 50% of kidney transplant patients. It is more prevalent in pediatric patients, and cyclosporine has added to the rates in both children and adults. Hypertension is an important risk factor for cardiovascular disease, which remains the leading cause of death for recipients of renal transplants. Fortunately, posttransplant hypertension is commonly mild to moderate in nature (transplant artery stenosis hypertension being the exception) and can be treated medically. However, the removal of native kidneys and the correction of arterial stenosis are two surgical interventions that are more common in the transplant population than in the general population. In posttransplant hypertension that is primarily due to cyclosporine, one must balance the risks of reduced cyclosporine dosage against the risks of the hypertension. Both diuretic and calcium channel blocker therapy are believed to be useful in cyclosporine-induced hypertension. Other vasodilators also may be effective, although they may have undesired effects on RBF and glomerular filtration.
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PMID:Cyclosporine and posttransplant hypertension. 149 82

The review summarizes recent data about the use of calcium channel blockers for the treatment of cardiovascular complications in patients with diabetes mellitus. It is shown that disturbances of Ca ion homeostasis play an important role in the pathogenesis of such diabetic complications as cardiomyopathy, microangiopathy, hypertension and the use of modern calcium channel antagonists for their treatment seems to be quite justified. However, despite definite positive effects of such treatment, these drugs should be used with care, especially if combined with derivatives of sulphonylurea as activators of the beta-cell function. Calcium channel blockers may intervene in the mechanism of the activity of beta-cells in which activation of the calcium channels is an obligatory link for triggering insulin secretion. Nevertheless, according to most of the authors, in such cases Ca antagonists can be recommended in moderate doses under continuous control of the hormonal status of the patient.
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PMID:[Current aspects of the mechanism of action of calcium antagonists in patients with diabetes mellitus]. 149 54

In choosing the optimum antihypertensive agent for an individual patient, various factors should be considered. Demographic characteristics (e.g., age, gender, race) and the circadian pattern of blood pressure elevation may influence the response to therapy. Concomitant therapy for coexisting medical disorders must be evaluated for possible drug interactions. Calcium channel blockers, which can be used in any age group, may be particularly useful in hypertensive patients with certain concurrent conditions (e.g., coronary artery disease, migraine, or gastrointestinal motility disorders). Life-style, including occupation and leisure-time activities, may contraindicate the use of certain drugs in a particular patient. It also may be necessary to consider the economic status of the patient, particularly in the elderly, who often have limited disposable income. Since to a great extent successful therapeutic management of hypertension depends on patient compliance, reduced frequency of dosing (i.e., once or twice daily) is desirable. The clustering of morbid events in the hours immediately following awakening highlights the need for therapy that provides 24-hour control, thereby ensuring adequate pharmacodynamic effects during that crucial period. The challenge is to select the most appropriate first-line agent (diuretic, beta blocker, calcium channel blocker, or angiotensin-converting enzyme inhibitor) for a particular patient.
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PMID:Selecting optimum antihypertensive therapy: indications for choosing a calcium channel blocker. 151 34

Although calcium channel blockers were only recently approved for antihypertensive therapy, 10 years of data have demonstrated their beneficial effects. Among the available calcium channel blockers, diltiazem hydrochloride appears to have a highly favorable side-effect profile. A new, extended-release formulation of diltiazem has been developed for the treatment of essential hypertension. The safety and efficacy of various once-daily doses of this new formulation were assessed in two multicenter studies. The first study was a dose-ranging trial of 275 patients with mild-to-moderate hypertension. Patients were randomly assigned to once-daily diltiazem (120, 240, 360, or 480 mg) or placebo for a 4-week, double-blind treatment period. A patient subgroup underwent ambulatory blood pressure monitoring (ABPM) twice. Once-daily diltiazem (dose range, 240-480 mg) significantly lowered trough systolic and diastolic blood pressure in a clearly dose-related fashion. ABPM results demonstrated consistent decreases in systolic and diastolic blood pressure throughout the 24-hour dosing interval. Dosages greater than or equal to 240 mg/day provided trough drug blood levels within the therapeutic range (i.e., greater than or equal to 40 ng/mL). The second study was a forced-escalation trail of 115 patients with mild-to-moderate hypertension. Patients were randomized to treatment with either placebo or escalating dosages of diltiazem (180 mg/day for 2 weeks, 360 mg/day for 2 weeks, and then 540 mg/day for 2 weeks). Statistically significant (p less than 0.01) reductions in supine systolic and diastolic blood pressure were observed with the 360 mg/day and 540 mg/day dosages. Dose escalations resulted in incremental blood pressure reductions and an increase in the percentage of responders. There was a significant correlation between diltiazem peak and trough plasma concentrations and antihypertensive effects in both studies, supporting the 24-hour efficacy of this extended-release formulation. Diltiazem administered once daily was found to be safe and well tolerated by the patients in these studies; adverse events were generally mild, with an incidence similar to placebo. Results indicate that this new extended-release formulation of diltiazem, administered once daily in doses greater than 120 mg, effectively lowers systolic and diastolic blood pressure in patients with mild-to-moderate essential hypertension.
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PMID:Clinical experience with a once-daily, extended-release formulation of diltiazem in the treatment of hypertension. 151 37

The authors report the successful control of labile hypertension associated with orthostatic hypotension in a 75-year-old male patient, by means of L-DOPS, a synthetic precursor of norepinephrine in combination with antihypertensive drugs. He had been known to be hypertensive for 15 years and developed a persistent floating sensation 2 years age. Despite good control of hypertension after admission, orthostatic hypotension was still observed. Passive tilt produced a blood pressure reduction of 60/20 mmHg. Spectral analysis of heart rate variability showed a disturbance in the activation of the sympathetic nervous system. Treatment with L-DOPS attenuated the blood pressure reduction in response to passive tilt (35/12 mmHg) and improved the sympathetic response. Because of an increase in blood pressure by L-DOPS, addition of either a calcium channel blocker or an angiotensin-converting enzyme inhibitor was necessary. These combinations of treatment successfully controlled blood pressure as well as orthostatic hypotension.
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PMID:[An elderly case of hypertension with persistent orthostatic hypotension]. 156 Jun 12

The use of calcium channel blockers (CCBs) in the treatment of hypertension and concomitant left ventricular dysfunction is reviewed. Some CCBs, particularly second-generation dihydropyridine agents such as felodipine, isradipine, nicardipine, nimodipine, and nitrendipine, have properties that enhance their usefulness in these patients. All CCBs have a similar mechanism of action. Differences in their selective action at various tissue sites determine which are most appropriate for patients with concomitant hypertension and left ventricular dysfunction. Most CCBs do not produce reflex stimulation of the heart or induce intravascular expansion. While all CCBs produce arteriolar dilation, all local beds and regional circulations in target organs are not affected equally. Most CCBs can decrease cardiac mass, and second-generation CCBs tend to have little or no negative inotropic effects at therapeutic dosages. In addition, they increase blood flow and reduce myocardial oxygen requirements. Because of differences in functional and electrophysiologic effects, specific CCBs may not be appropriate for all patients. Since second-generation dihydropyridine CCBs lack clinically relevant negative inotropic effects, and have been shown to improve exercise tolerance and coronary artery perfusion, they are appropriate for hypertensive patients with left ventricular dysfunction, angina, and coronary heart disease. Second-generation CCBs tend to lack cardiodepressant side effects and are less likely to react with digoxin than are first-generation CCBs.
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PMID:Efficacy and safety of calcium channel blockers in hypertensive patients with concomitant left ventricular dysfunction. 156 26

Scorpion envenomation is a common medical problem and life hazard in many countries of the world. Scientific investigations have addressed the interrelationship between the stimulatory effects of the venom on the autonomic nervous system and adrenals and the subsequent effects of released transmitters on the cardiovascular system. A number of clinical cardiovascular syndromes may dominate the initial clinical presentation after envenomation: the syndromes usually vary with the age of the victim, the size of the offender and the season. Central nervous system dysfunction is seen in children but rarely observed in adults; if accompanied by severe hypertension the clinical picture is consistent with acute hypertensive encephalopathy. Heart failure, pulmonary edema or a shock-like syndrome has been observed in 25% and hypertension in 30% to 77% of our patients. The electrocardiographic abnormalities recorded in the majority of the patients after envenomation include an "acute myocardial infarction-like pattern." Rhythm disturbances are frequent but conduction abnormalities are rare. Echocardiographic, radionuclide and experimental hemodynamic observations have provided evidence that heart failure and pulmonary edema after envenomation are multifactorial with diminished systolic performance following the initially increased left ventricular contractility and decreased ventricular diastolic compliance. Clinical laboratory data reporting increased catecholamine metabolite excretion and elevated plasma renin and aldosterone are consistent with the stimulatory effects of the venom on the autonomic nervous system. Treatment, including our experience with vasodilators and calcium channel blockers, is reviewed.
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PMID:The cardiovascular system after scorpion envenomation. A review. 158 74

Hypertension should be detected and treated early in diabetic patients. It markedly affects the morbidity and mortality of diabetic individuals as a result of both atherosclerosis and microvascular disease. Antihypertensive treatment is an effective tool in slowing the progression of early and advanced diabetic nephropathy. No prospective studies have addressed the effects of antihypertensive regimens on the incidence of congestive heart failure, stroke, and coronary artery disease in large groups of diabetic patients. Such studies are urgently needed. Special consideration should be given to the effects of antihypertensive drugs on glycemic control and the lipid profile of the diabetic patient. Because hyperinsulinemia (and insulin resistance) have been advocated as hypertensive and atherosclerotic risk factors, the effects of antihypertensive drugs on insulin action and plasma insulin levels may become an important element in the selection an antihypertensive agent. More information, however, is needed in these areas. ACE inhibitors, calcium channel blockers, and alpha-adrenergic blockers probably offer a more favorable metabolic profile as compared with diuretics and beta-blockers. The former agents should be used as initial drugs in most clinical settings.
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PMID:Management of hypertension in diabetes. 161 71

This randomized double-blind parallel group study characterized the pharmacokinetics of the calcium channel antagonist, nisoldipine (core-coat tablets), administered once daily for 7 days in doses of 5 mg (n = 12), 10 mg (n = 13), 20 mg (n = 12), and 30 mg (n = 11) to patients with mild to moderate hypertension. Serial blood samples were obtained from 0 to 24 hours and from 0 to 48 hours after nisoldipine administration on days 1 and 7, respectively. Nisoldipine plasma concentrations were determined by gas chromatography with electron capture detection. No statistically significant difference was found in dose-normalized area under the curve between the four groups. Area under the curve (standardized to body weight) correlated to dose (r = .74, P less than .05). No significant difference existed in oral clearance (L/h/kg) when analyzed for equivalence across the four doses: 8.21 +/- 3.47 (5 mg), 11.84 +/- 13.85 (10 mg), 11.48 +/- 7.49 (20 mg), and 10.36 +/- 5.49 (30 mg). The present investigation characterizes the pharmacokinetics of nisoldipine core-coat tablets in hypertensive patients and demonstrates the dose proportionality or linearity of nisoldipine plasma concentrations and area under the curve, measured over a dose range of 5 to 30 mg.
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PMID:Multiple dose pharmacokinetics of four different doses of nisoldipine in hypertensive patients. 163 46


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