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

This review attempts to highlight the potential of calcium-channel blockers in the prevention of sequelae of diabetes mellitus and hypertension in patients who have both disorders. Evidence-based medicine is driven by the results of randomized, clinical trials. Major contributions were therefore derived from post hoc analyses of the diabetic patients enrolled in placebo-controlled trials, such as Systolic Hypertension in the Elderly Program (SHEP), Systolic Hypertension in Europe (Syst-Eur), and Systolic Hypertension in China (Syst-China), and stepped-care blood-pressure-oriented trials, such as the Hypertension Optimal Treatment (HOT) and United Kingdom Prospective Diabetes Study (UKPDS). Several studies, such as the Fosiniprl; versus Amlodipine Cardiovascular Events Trial (FACET) and Appropriate Blood Pressure Control in Diabetes (ABCD) Trial, have compared the relative merits of angiotensin-converting enzyme and calcium-channel blockers in preserving renal function and metabolic balance in diabetic patients with hypertension, but their publications focused on cardiovascular disorders, which were only secondary end points. On balance, the articles reviewed prove that dihydropyridine calcium-channel blockers score particularly well in the prevention of cardiovascular complications in diabetic patients with hypertension.
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PMID:Treatment of diabetic patients with hypertension. 1098 Oct 70

The purpose of the present study was to investigate whether treatment of male rats with the calcium antagonist amlodipine, used in the treatment of hypertension and angina, interferes with the reproductive function of male rats. Amlodipine treatment (0.04 mg amlodipine besylate/rat/day for 30 days) decreased plasma follicle-stimulating hormone and testosterone but not luteinizing hormone or prolactin concentrations (measured by double-antibody radioimmuno-assay). A significant reduction (23%) was observed in sperm density (sperm suspension collected from the cauda epididymidis) as well as in the amount of mature spermatids (14%) and Sertoli cells (9%) counted in seminiferous tubule cross-sections (400 x magnification). The results reveal the deleterious effects of subacute amlodipine treatment on the reproductive function of male rats.
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PMID:Antireproductive effect of the calcium channel blocker amlodipine in male rats. 1098 90

Amlodipine, a long-acting dihydropyridine calcium channel blocking agent, was administered to 55 children (age: 11.5 +/- 5.4 years) with hypertension, 49 of whom (89%) had secondary hypertension. Efficacy was assessed by comparing pretreatment blood pressure (BP) to follow-up BP obtained in our outpatient Pediatric Nephrology clinic. Thirty-two (58%) patients achieved BP control with amlodipine alone, and 31 (55%) patients received amlodipine twice daily. Eleven patients received amlodipine as a suspension. Mean amlodipine dose was 0.16 +/- 0.12 mg/kg/day; there was an inverse relationship between patient age and amlodipine dose. Follow-up BP were significantly lower than pretreatment BP: systolic BP fell from 129 +/- 12 to 122 +/- 12 mm Hg (P = .004), and diastolic BP fell from 78 +/- 13 to 70 +/- 19 mm Hg (P = .003). A small, clinically insignificant increase in heart rate (from 91 +/- 19 beats/min to 99 +/- 26 beats/min; P = .02) occurred during amlodipine treatment. Adverse effects reported included dizziness (three patients), fatigue (two patients), flushing (two patients), and leg edema (one patient). All improved with dose reduction. We conclude that amlodipine provides effective BP control without significant adverse effects in children with hypertension, and can be used as monotherapy in most children. Young children appear to require significantly higher doses per kilogram of body weight than older children. Twice-daily dosing may be required in many children to achieve BP control. Detailed pharmacokinetic studies are needed to confirm these observations.
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PMID:Treatment of hypertensive children with amlodipine. 1104 Nov 59

Amlodipine is a calcium channel antagonist of the dihydropyridine group. It is effective for treating hypertension, chronic stable angina, and vasospastic angina. However, it is difficult clinically to pinpoint the maximum dosage for antihypertensive activity of the drug without having parallel data on the plasma drug concentrations. The methods for assaying amlodipine are either gas chromatography with electron capture detector or liquid chromatography coupled with tandem mass spectrometry (or with an electrochemical detector), which needs tedious derivatization, and is expensive and time consuming. Therefore, in this study we developed an enzyme immunoassay for determining amlodipine in plasma. Anti-amlodipine antibodies were produced following immunization of bovine serum albumin-amlodipine conjugate. These specific antibodies were used in a competitive biotin-avidin-based enzyme-linked immunosorbent assay to measure amlodipine in plasma. Biotin was linked to the antibodies in order to enhance the sensitivity of the assay. The assay was specific for the free form of amlodipine with a detection limit of 0.1 ng/ml and the intra- and interassay coefficient of variation ranged from 1.6-10.2%. This immunoassay provides a sensitive, reliable, rapid, and accurate method for determination of amlodipine in plasma, which can be used in therapeutic drug monitoring pharmacokinetic studies and pharmaceutical analysis.
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PMID:Enzyme linked immunosorbent assay for determination of amlodipine in plasma. 1117 Feb 35

Hypertension and hyperfiltration are two important risk factors for the development of chronic allograft nephropathy. Transforming growth factor-beta(1) (TGF-beta(1)) is the main cytokine involved in the fibrotic process that is involved in chronic rejection. Angiotensin II upregulates TGF-beta(1) production. Angiotensin II receptor antagonists therefore could not only control BP but also reduce TGF-beta(1) production in renal transplant patients. The aim of this study was to compare the effects of losartan and amlodipine on renal hemodynamics, as well as TGF-beta(1) and endothelin-1 (ET-1) plasma levels in a group of renal transplant patients who had normal renal function and who were treated with cyclosporine. Seventeen renal transplant patients who were receiving cyclosporine and who had normal graft function were included in a random 2 x 2 crossover trial with amlodipine and losartan (6 wk with each therapy). Three studies were performed (at baseline and at the end of both treatment periods) to determine renal hemodynamics, TGF-beta(1), and ET-1. Both treatments controlled BP to a similar degree, but only amlodipine increased GFR through an increase in the estimated glomerular hydrostatic pressure and filtration fraction. In contrast, losartan maintained GFR and reduced estimated glomerular hydrostatic pressure and filtration fraction significantly. Losartan and amlodipine had opposite effects on TGF-beta(1). Amlodipine did not affect TGF-beta(1) concentrations. In contrast, losartan reduced the plasma levels of TGF-beta(1) by approximately by 50% (from baseline, 5.2 to 2.6 ng/ml; P: = 0.01); the majority of the patients reached normal levels of TGF-beta(1). ET-1 concentrations were significantly higher during amlodipine compared with losartan treatment. The present study documents that with similar control of BP, losartan and amlodipine have opposite effects on renal hemodynamics and on TGF-beta1 concentrations. These differences could be important for the management of chronic allograft nephropathy.
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PMID:Effects of losartan and amlodipine on intrarenal hemodynamics and TGF-beta(1) plasma levels in a crossover trial in renal transplant recipients. 1127 44

Systolic hypertension was diagnosed in 30 cats. At diagnosis, 16 of those were found to be in chronic renal failure only, while five were azotaemic and either receiving treatment for hyperthyroidism (four cases) or were untreated hyperthyroid cases (one case). Two cases were untreated hyperthyroid cases with no evidence of azotaemia and the remaining seven cases had no definitive diagnosis of the underlying cause of their hypertension. The successful treatment used for the majority of cases was amlodipine, which lowered systolic blood pressure from 202.5+/-16.8 to 153.2+/-21.6 mmHg (mean+/-SD; n=29) within the first 50 days. Each case was followed for at least three months, or to the end of its natural life, and each cat was re-examined every six to eight weeks. Systolic blood pressure was kept below a target value of 165 mmHg in 58 per cent of cases treated for three months or longer. At the time of writing, 19 of the cases had died or been euthanased with a median treatment time of 203 days, one case was lost to follow-up and 10 cases were still alive, nine of which had been treated for six months or more. Amlodipine can be used for long-term control of feline systemic hypertension.
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PMID:Feline hypertension: clinical findings and response to antihypertensive treatment in 30 cases. 1130 54

Myocardial infarction, stroke, heart failure and end-stage renal disease have all been linked to inadequate control of blood pressure. Despite overwhelming evidence that uncontrolled hypertension is responsible for a sizeable number of adverse health-related outcomes, control of the disease remains considerably suboptimal. Available data demonstrate that in order to achieve adequate blood pressure control, a large number of patients require therapy with more than one medication. Fixed dose combination antihypertensive therapy has many advantages over other treatment options. Positive effects on blood pressure control, rates of adherence, adverse effects and cost have been identified. Amlodipine/benazepril (Lotrel), Novartis) is a fixed dose combination product indicated for the treatment of hypertension. Although not currently recommended as first-line therapy, studies confirm that this combination of a long-acting calcium antagonist and an angiotensin-converting enzyme (ACE) inhibitor possesses substantial blood pressure lowering capabilities. Whereas adverse events tend to become more frequent with increasing doses of antihypertensive monotherapy, the rate of adverse events attributed to amlodipine/benazepril in clinical trials often correlates with rates ascribed to placebo. Amlodipine/benazepril is capable of sustaining blood pressure control over a 24 h period and appears to be minimally affected by an occasional dose omission. Unlike the older calcium antagonists, amlodipine is unlikely to cause alterations in myocardial contractility. Additionally, the amlodipine/benazepril combination product costs less than the same therapy administered as the individual components. It is, therefore, reasonable to consider therapy with amlodipine/benazepril in appropriate patients after an adequate trial of antihypertensive monotherapy.
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PMID:Amlodipine/benazepril: fixed dose combination therapy for hypertension. 1133 77

The aim of the present study was to compare the effects of a long-acting dihydropyridine (amlodipine) and a nondihydropyridine (verapamil) on autonomic function in patients with mild to moderate hypertension. A total of 145 patients with a diastolic blood pressure (BP) between 95 and 110 mm Hg received 8 weeks of verapamil sustained release (240 mg) and amlodipine (5 mg) in a prospective randomized, double blind, cross-over study, both after 4 weeks of placebo. The 24-h autonomic balance was measured by analysis of 24-h heart rate variability and short-term autonomic control of BP by baroreflex sensitivity measurements. Plasma norepinephrine was sampled at rest. Blood pressure was equally reduced from 153/100 mm Hg to 139/91 mm Hg with verapamil and 138/91 mm Hg with amlodipine, P = .50/.59. The low- to high-frequency ratio (LF/HF), reflecting sympathovagal balance, was higher with amlodipine than with verapamil (4.66 v 4.10; P = .001). Baroreflex function was improved by both treatments; however, baroreflex sensitivity (BRS) was significantly higher with verapamil than with amlodipine (8.47 v 8.06 msec/mm Hg; P = .01). Plasma norepinephrine (NE) level was higher with amlodipine than with verapamil (1.59 v 1.32 nmol/L; P < .0001). Amlodipine induces a shift in sympathovagal balance, as measured by heart rate variability indices and plasma NE, toward sympathetic predominance compared with vagal predominance with verapamil. Short-term autonomic control of BP, as assessed by BRS, is more effectively improved by verapamil than by amlodipine. These contrasting effects on autonomic function suggest that the nondihydropyridine calcium antagonist verapamil may have additional beneficial effects beyond lowering BP compared with the dihydropyridine amlodipine.
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PMID:The effects of dihydropyridine and phenylalkylamine calcium antagonist classes on autonomic function in hypertension: the VAMPHYRE study. 1172 4

The purpose of this study was to determine whether there are differences in the restoration of endothelial function by angiotensin-converting enzyme inhibition based on the severity of hypertension. Forearm blood flow (FBF) was measured in 69 patients with essential hypertension (mild, n = 23; moderate, n = 29; and severe, n = 17 randomly assigned to treatment with either imidapril or amlodipine for 24 weeks in a double-blind fashion during reactive hyperemia and after sublingual administration of nitroglycerin. Imidapril augmented the FBF response to reactive hyperemia after 24 weeks of treatment in the mild and moderate hypertensive groups, but not in the severe hypertensive group. The augmentation of the FBF response to reactive hyperemia induced by imidapril was significantly greater in the moderate hypertensive group than in the mild hypertensive group. Amlodipine did not alter the FBF response to reactive hyperemia. The increase in FBF after the sublingually administered nitroglycerin was similar in all groups. The infusion of NG-monomethyl-l-arginine, a nitric oxide synthase inhibitor, abolished the enhancement of reactive hyperemia in the mild and moderate hypertensive groups treated with imidapril. These findings suggest that the effects of imidapril on endothelial function are affected by the severity of hypertension and that angiotensin-converting enzyme inhibitor-induced augmentation of reactive hyperemia may be due to increased nitric oxide production.
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PMID:Severity of hypertension affects improved resistance artery endothelial function by angiotensin-converting enzyme inhibition. 1197 10

Recent trials have helped to clarify indications for the initial pharmacological therapy of hypertension. Both the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) and World Health Organization-international Society of Hypertension (WHO-ISH) recommendations should be revised. The more recent trials indicate that: (1) diuretics and beta-blockers appear to be as effective in reducing overall morbidity/ mortality as other agents (Swedish Trial in Old Patients with Hypertension [STOP-2], United Kingdom Prospective Diabetes Study [UKPDS], Intervention as a Goal in Hypertension Treatment [INSIGHT], Nordic diltiazem [NORDIL]); (2) the use of an a-blocker results in more cardiovascular events, especially congestive heart failure, when compared with a diuretic (Antihypertensive Therapy and Lipid Lowering Heart Attack Trial [ALLHAT]); (3)the use of an angiotensin-converting enzyme (ACE) inhibitor results in fewer myocardial infarctions and episodes of heart failure than calcium channel blockers in the elderly and in diabetic patients (Fosinopril vs. Amlodipine Cardiovascular Events Randomized Trial [FACET], Appropriate Blood Pressure Control in Diabetes [ABCD], STOP-2) - other data (Captopril Prevention Project [CAPPP]) suggest that the use of an ACE inhibitor is preferred in diabetic patients; (4) overall cardiovascular events are similar with calcium channel blockers compared with a diuretic - however, there are fewer strokes with non-dihydropyridine calcium channel blockers (NORDIL) and a trend towards an increase in heart failure and myocardial infarctions with either a dihydropyridine or non-dihydropyridine calcium channel blockers compared with a diuretic (INSIGHT, NORDIL); (5) angiotensin receptor blockers (ARBs) will decrease proteinuria and slow progression of renal disease in type 2 diabetic patients when compared with regimens that do not include an ARB or an ACE inhibitor (Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan [RENAAL], Irbesartan Type II Diabetic Nephropathy Trial [IDNT], Irbesartan Type II Diabetes with Microalbuminuria [IRMA Il]). The debate over initial therapy may be moot. High-risk hypertensive patients should probably be treated initially with combination therapy, one of which should be a diuretic. The use of diuretics and beta-blockers as well as ACE-inhibitors alone or with a diuretic should be considered as initial therapy (a change from JNCVI). Alpha-blockers should be reserved for special situations, i.e. prostatic hypertrophy (in contrast to WHO-ISH recommendations). An ACE-inhibitor or ARB, usually along with a diuretic, can be considered as preferred therapy in hypertensive diabetic patients. Some data suggest equal or greater reduction in strokes with a calcium channel blocker than other medications.
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PMID:Current recommendations for the treatment of hypertension: are they still valid? 1199 97


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