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

The chemistry, pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and dosage of enalapril maleate, a nonsulfhydryl angiotensin-converting enzyme (ACE) inhibitor, are reviewed. Enalapril is rapidly converted by ester hydrolysis to enalaprilat, a potent ACE inhibitor; enalapril itself is only a weak ACE inhibitor. Enalapril lowers peripheral vascular resistance without causing an increase in heart rate. In patients with congestive heart failure, enalapril has beneficial hemodynamic effects based on reduction of both cardiac preload and afterload. Approximately 60% of a dose of enalapril is absorbed after oral administration. Excretion of enalaprilat is primarily renal. Accumulation of enalaprilat occurs in patients with creatinine clearances less than 30 mL/min. Enalapril 10-40 mg per day orally has shown efficacy comparable to that of captopril in treating patients with mild, moderate, and severe hypertension, hypertension caused by renal-artery stenosis, and in congestive heart failure resistant to digitalis and diuretics. When given alone for hypertension, enalapril has efficacy comparable to that of thiazide diuretics and beta blockers. Side effects observed with enalapril have generally been minor. Captopril-associated side effects such as skin rash, loss of taste, and proteinuria have been observed in a small number of patients receiving enalapril to date; neutropenia less than 300/mm3 has been noted with captopril but not enalapril. The incidence of these side effects has been noted to be greatly decreased in patients on low doses of captopril. Enalapril appears to be similar in efficacy to captopril for treating hypertension and congestive heart failure. Whether enalapril is safer than low-dose captopril in patients at high risk for captopril-associated side effects will require further investigation.
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PMID:Enalapril, a nonsulfhydryl angiotensin-converting enzyme inhibitor. 298 41

Angiotensin-converting enzyme (ACE) inhibitors are a new class of drugs, whose main indications are the treatment of hypertension and of heart failure. Data obtained with captopril, the first orally active ACE inhibitor, affords an understanding of the rationale of their therapeutic use based on the knowledge of their mechanisms of action, efficacy, contraindications and precautions, dosage and frequency of administration, side-effects, interactions and advantages. ACE inhibitors appear to exert their haemodynamic effect mainly by inhibiting the renin-angiotensin-aldosterone system, but also by modulating sympathetic nervous system activity and by increasing prostaglandin synthesis. Therefore they act both on vasoconstrictor and volume factors, since they cause vasodilation (the main effect) and mild natriuresis without affecting the heart rate and contractility and, probably, favourably influencing renal, coronary and cerebral circulation. So far it appears that ACE inhibitors can be usefully employed in the treatment of heart failure, in which they reduce both pre- and after-load, and mainly of hypertension. In the past captopril has been used to treat only severe and or resistant hypertension and some secondary forms, like renal parenchymal and renovascular hypertension, but now it seems that captopril is useful also to treat mild to moderate essential hypertension. Their efficacy in reducing blood pressure is similar to that of thiazide diuretics and of beta-blockers, the two drugs now considered of first choice and they exert their hypotensive action without the development of pseudotolerance or tolerance. ACE inhibitors seem, at the moment, contraindicated in pregnancy and in hyperkalaemic syndromes and must be used with caution in patients with collagen disease (mainly associated with renal failure), with severe bilateral renal artery stenosis (and with severe artery stenosis of a solitary kidney) and with severe sodium depletion. It is now established that captopril has a flat dose response curve and that it must be given (twice daily) at a dose not exceeding 150 mg/day. The same pharmacological approach must be used with future ACE inhibitors in order to establish the right posology and the frequency of administration. In this respect enalapril seems to be a promising ACE inhibitor with a prolonged action (at least 24 hours). The exact posology of ACE inhibitors might be crucial, since it has been shown that the side-effects of captopril (skin rashes, fever, taste disturbances, proteinuria and neutropenia) are dose dependent.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Angiotensin-converting enzyme inhibitors in hypertension: a review. 300 82

Numerous trials have shown the efficacy of ACE-inhibitors in moderate and severe essential hypertension. Their use must be regarded as very promising. They lower peripheral vascular resistance without influencing cardiac index and heart rate. Additionally, they maintain serum potassium and do not effect plasma lipids or provoke diabetes mellitus or gout. In 20-30% of hypertensive patients ACE-inhibitors have to be combined with diuretics and/or calcium antagonists. The addition of beta-blockers is useful in patients with resting tachycardia. In mild hypertension the use of ACE-inhibitors as first-line drugs is indicated in patients with adverse reactions to beta-blockers or diuretics. In bilateral renovascular hypertension, ACE-inhibitors may induce a strong blood pressure fall; in bilateral stenosis they contribute to a deterioration of renal function with reversible renal insufficiency. In renoparenchymal hypertension, ACE-inhibitors may attenuate the progression of renal insufficiency; in addition, proteinuria is lowered. In systolic hypertension in the elderly, one must be aware of a marked first-dose hypotensive effect. ACE-inhibitors decrease exaggerated exercise-induced elevation of blood pressure and heart rate and therefore lower myocardial oxygen consumption. In patients with hypertension and diabetes mellitus, antihypertensive treatment should be initiated for blood pressure levels above 140/90 mmHg, to attenuate the progression of vascular damage in the kidney. In patients with severe left ventricular hypertrophy, ACE-inhibitors reduce left ventricular mass within three months by about 30%. In hypertension and coronary heart disease, recent studies report benefits of ACE-inhibitors on coronary circulation. Presently available ACE-inhibitors and those in preparation do not differ in pharmacodynamic, but in pharmacokinetic properties, concerning the beginning and duration of blood pressure lowering. A hypotensive first-dose effect can be observed in diuretic pretreated patients, in severe (malignant) and renovascular hypertension. ACE-inhibitors should not be used during pregnancy or in patients with autoimmune diseases or those undergoing treatment with immunosuppressive drugs, due to the side effects of neutropenia and proteinuria, which are more often seen under these conditions. Results from long-term studies on the influence of ACE-inhibitor treatment on cardiovascular risk in mild hypertension have not been available until now. In the decision to treat mild hypertension with ACE-inhibitors as first-line drug therapy, the costs of therapy in comparison to cheaper antihypertensives must be taken into account.
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PMID:[The value of angiotensin-converting enzyme inhibitors in the treatment of hypertension]. 306 60

This review will discuss the safety profiles of the angiotensin-converting enzyme (ACE) inhibitors captopril, enalapril and lisinopril in patients with hypertension. In general, the safety profiles of ACE inhibitors compare favourably with those of other agents used for the treatment of hypertension. Adverse effects are not common when ACE inhibitors are used at the currently recommended doses. The adverse experiences that do occur with ACE inhibitors can be divided into 3 categories. Hypotension, hyperkalaemia and renal impairment are related directly to the blockade of the angiotensin-converting enzyme. Attention to the clinical condition, including concomitant therapy, reduces the risk of these adverse effects of ACE inhibition. Other adverse effects such as cough and angioedema also occur with all ACE inhibitors. The mechanisms are poorly understood, making it difficult to predict in which patients they will occur. Adverse effects such as rash, dysgeusia, neutropenia and proteinuria, which were reported relatively frequently in the early experience with captopril, are reported less frequently with lower doses of captopril and do not appear to be a problem with other ACE inhibitors such as enalapril and lisinopril.
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PMID:Safety profiles of the angiotensin-converting enzyme inhibitors. 306 90

Captopril is an orally active inhibitor of angiotensin-converting enzyme (ACE) and has been widely studied in the treatment of patients with mild to moderate essential hypertension, severe hypertension not responsive to conventional diuretic/beta-adrenoceptor blocker/vasodilator regimens, and patients with chronic congestive heart failure refractory to treatment with a diuretic and digitalis. In patients with mild or moderate essential hypertension, titrated low doses of captopril used alone or in conjunction with a diuretic are similar in efficacy to usual doses of hydrochlorothiazide, chlorthalidone, or beta-adrenoceptor blocking drugs, as well as to the other ACE inhibitors. In addition, captopril improved well-being to a greater extent than methyldopa or propranolol in a study designed specifically to determine the effect of treatment on the quality of life of patients with mild or moderate essential hypertension. The earlier demonstrated efficacy of captopril, used with a diuretic and often also with a beta-adrenoceptor blocking drug, in the treatment of severe hypertension refractory to conventional 'triple therapy' has been confirmed in more recent trials which illustrate the generally marked antihypertensive effect of captopril-containing regimens in such patients. Results of initial trials in patients with scleroderma are promising, with control of hypertension and stabilization of renal function in these patients when treated at an early stage of the disease. Several comparative and long term trials of captopril in patients with chronic congestive heart failure refractory to treatment with a diuretic/digitalis regimen clearly demonstrate that initial haemodynamic improvement is maintained and correlates with clinical benefit. A tendency for overall clinical response to captopril to be better than the response to prazosin, hydralazine, nisoldipine or enalapril has been reported. Results of a multicentre comparison with digoxin and placebo indicate that captopril is a suitable alternative to digoxin in patients with mild to moderate heart failure who are receiving maintenance diuretic therapy. The tolerability of captopril has now been studied in many thousands of patients involved in formalized trials and the early impression of poor tolerability can no longer be justified. The use of generally lower dosages of captopril in patients with normal or slightly impaired renal function has resulted in a generally low incidence of rash (0.5 to 4%), dysgeusia (0.1 to 3%), proteinuria (0.5%), neutropenia (0.3% during first 3 months) and symptomatic hypotension (0.1 to 3%). Cough is an infrequent but troublesome effect resulting from ACE inhibition.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Captopril. An update of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in hypertension and congestive heart failure. 306 99

When captopril was first introduced, it was used in high doses for severe hypertension, often in the presence of renal insufficiency, and side effects such as proteinuria, rash, neutropenia, and altered taste sensation were noted. Upon analysis, these effects were most commonly seen in patients with renal disease, autoimmune disease, or collagen vascular disease. These complications usually reversed rapidly upon discontinuation of treatment. In contrast, the growing use of the angiotensin converting enzyme inhibitors, captopril and enalapril, for treating mild to moderate hypertension and the trend toward the use of lower doses has shown these agents to be well tolerated with a low frequency of troublesome adverse effects. In fact, the original spectrum of adverse effects has virtually disappeared with the use of lower doses in patients with uncomplicated hypertension. In low doses, the converting enzyme inhibitors produce remarkably few incidences of symptomatic discomfort; the most common is skin rash, which often responds to dosage reduction. Cough and rare occurrences of angioedema have also been reported. Moreover, evidence is evolving that indicates that the converting enzyme inhibitors may sometimes decrease proteinuria and improve renal function; these effects may be especially important in diabetic hypertensive patients. Of note, these drugs can also attenuate the unwanted metabolic side effects of concurrent diuretic treatment.
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PMID:Safety issues during antihypertensive treatment with angiotensin converting enzyme inhibitors. 306 5

Neutrophils have been implicated in the pathogenesis of acute lung injury associated with clinical and experimental sepsis. Data from in vitro systems and experimental animals have suggested that neutrophil-derived oxidants, particularly H2O2, may be primarily responsible for endothelial damage, vasoconstriction, and lung edema. With the use of endotoxin infusion as an in vivo model of sepsis we tested the hypothesis that pretreatment with catalase, a peroxide scavenger, would ameliorate the resultant changes in pulmonary vasoconstriction and lung fluid balance. Paired experiments were performed in 16 goats with chronic lung lymph fistulas. One group of animals (n = 7) received endotoxin first alone and then again, several days later, after pretreatment with Ficoll-linked catalase. As a control, identical experiments were performed in a separate group (n = 6) with Ficoll-linked albumin substituted for Ficoll-catalase. A third group (n = 3) was given endotoxin alone and then again during a continuous infusion of catalase. Plasma and lymph levels of catalase were comparable to or exceeded those previously shown to be completely protective in isolated perfused lung preparations and in vitro systems. Endotoxin caused neutropenia, pulmonary arterial hypertension, decreased cardiac output, and increases in lymph flow to approximately three times base line, with a return of all variables toward control values by 6 h. Catalase pretreatment produced no significant differences in any of these variables. These experiments do not support a role for H2O2 as a mediator of acute lung injury due to endotoxemia.
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PMID:Effect of intravenous catalase on the pulmonary vascular response to endotoxemia in goats. 328 99

Lipid X (2,3-diacylglucosamine-1-phosphate) is a novel monosaccharide precursor of lipid A that has some of the physiologic activities of endotoxin but little toxicity. To determine whether lipid X would interfere with the toxic effects of endotoxin, we pretreated sheep with either 100 or 200 micrograms of lipid X per kg of body weight and then challenged them with a potentially fatal dose of Escherichia coli endotoxin (20 micrograms/kg). Twenty-one sheep underwent pulmonary artery catheterization and were monitored for changes in pulmonary artery pressure, temperature, pH, partial O2 pressure, partial CO2 pressure, blood pressure, and cell counts over 7 h. Overall mortality for control animals was 37% versus 5.3% for pretreated animals. None of the 13 animals pretreated with 100 micrograms of lipid X per kg died. These differences in survival were significant (P less than 0.05). Animals pretreated with 100 micrograms of lipid X per kg had significantly lower pulmonary artery pressure during both phases 1 and 2 of endotoxin-induced pulmonary artery hypertension. A higher dose of lipid X, 200 micrograms/kg, produced pulmonary hypertension. Perhaps because lipid X is a subunit of lipid A, lipid X shows a partial pyrogenic effect while also decreasing the pyrogenic activity of complete lipopolysaccharide (LPS). Lipid X did not prevent endotoxin-induced neutropenia or moderate hypotension in response to LPS. Lipid X is a potential prototype compound for a new type of chemotherapy directed at blocking the harmful effects of LPS during bacterial septicemia.
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PMID:Lipid X ameliorates pulmonary hypertension and protects sheep from death due to endotoxin. 330 7

Hypotension, bradycardia, pulmonary artery hypertension, neutropenia, and thrombocytopenia have been suspected to be due to complement activation following protamine reversal of heparin. This investigation examined these phenomena in complement-depleted animals. Eight dogs received intraperitoneal naja n. naja cobra venom factor (CVF), 20 U/kg, 48 and 24 hr prior to anticoagulation with sodium heparin, 150 IU/kg, and reversal 30 min later with protamine sulfate, 1.5 mg/kg. Decomplementation was confirmed in all dogs. Systemic blood pressure (BP), pulse (HR), pulmonary artery systolic and diastolic pressures, (PAS, PAD), cardiac output (CO), platelet count (PTC), and white blood count (WBC) with differential were monitored. The maximal mean changes for the entire group were BP, -43 mm Hg; HR, -16; PAS, +6 mm Hg; PAD, +3 mm Hg; CO, -27%; PTC, -49%; and WBC, -48%. These hemodynamic and hematologic responses, occurring in the face of CVF-induced decomplementation, support the conclusion that complement components C3 and C5-C9 are not influential factors contributing to these protamine-heparin-induced events.
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PMID:Complement depletion and persistent hemodynamic-hematologic responses in protamine-heparin reactions. 341 56

This investigation was performed in two groups of adult patients, 10 with type I and 10 with type II diabetes mellitus, all with arterial hypertension (160 to 200 mm Hg systolic and 95 to 120 mm Hg diastolic). Captopril, 50 mg twice a day, was administered for 12 weeks and was effective as monotherapy in 16 patients. Mean arterial pressure (+/- s.d.) in type I patients changed from 121.4 +/- 9.6 to 100.2 +/- 10.1 after 4 weeks and to 102.0 +/- 3.8 mm Hg after 12 weeks; in type II patients it changed from 132.8 +/- 5.7 to 123.9 +/- 13.5 after 4 weeks and to 109.1 +/- 11.1 mm Hg after 12 weeks. The differences were statistically significant. In only 4 patients was it necessary to add a thiazide after the first month of therapy. No significant change was induced by captopril in urine output, osmolar clearance, free water clearance inulin, and PAH clearances. No significant change was observed in serum and urine Na+, Cl-, Ca++ and Mg++, whereas a statistically significant reduction was found in the renal clearances of K+ and PO4-. No important change in serum aldosterone was found, while plasma renin activity was increased, as expected. No alterations in urine protein, glucosaminoglycans, gamma GT, and N-acetyl-beta-glucosaminidase were observed during follow-up. All patients maintained good metabolic control of their disease. No neutropenia and orthostatic hypotension were seen. Captopril appears to be an effective and safe drug for lowering blood pressure in diabetic patients, without affecting renal function, electrolyte balance and the metabolic control of diabetes.
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PMID:Captopril in the treatment of hypertension in type I and type II diabetic patients. 353 66


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