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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diuretics and beta blockers are the mainstay in treating mild and moderate systemic hypertension, but there is controversy as to which should be used first. Recent evidence of an increase in sudden death and a greater number of intolerable side effects in the diuretic-treated groups in the Multiple Risk Factor Intervention Trial in the U.S. and the Medical Research Council Trial in Great Britain has prompted some to suggest beta blockers as first-line therapy. However, beta blockers also have side effects, such as decreased ventricular function in patients with mild heart failure, increased airways resistance in those with chronic obstructive lung disease, increased plasma lipids, in particular low density lipoprotein cholesterol, and increased problems in patients with peripheral vascular disease and those with diabetes requiring insulin treatment. Many new beta-blocking drugs with different pharmacokinetic and pharmacodynamic properties allow the physician to choose the best one for each patient. beta-blocking drugs with long durations of action, high levels of bioavailability, beta 1 selectivity and intrinsic sympathomimetic activity appear most suitable for therapy. Cardioselectivity is suggested for patients with obstructive lung disease and peripheral vascular disease, and diabetic patients who take insulin. Long durations of action permit infrequent administration and recently agents with intrinsic sympathomimetic activity have been shown to have less effects on plasma lipid levels. Acebutolol also reduces ventricular arrhythmias, and may therefore be used to reduce sudden death in patients with coronary artery disease. The pharmacokinetic and pharmacodynamic properties of beta-blocking drugs can indicate the most appropriate choice for hypertensive patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pharmacokinetic and pharmacodynamic properties of beta-blocking drugs influencing choice in treatment of systemic hypertension. 288 49

To establish the criteria for the selection of a beta-adrenergic blocking agent (beta-blockers) suitable for the long-term treatment of tremor, 20 patients with essential tremor were treated with five different types of beta-blockers. All beta-blockers were effective for essential tremor, but their efficacy differed. The weaker the intrinsic sympathomimetic activity (ISA) and the more marked the membrane stabilizing activity (MSA), the more marked was the anti-tremor effect. Propranolol, which showed the strongest anti-tremor effect, had no ISA, but its long-term administration induced symptoms of heart failure, such as pretibial oedema, in most cases. In most of these cases, when propranolol was replaced by indenolol, which showed a very slight ISA, the pretibial oedema subsided and well-controlled tremor was maintained over a long period. With regard to efficacy and usefulness, it was thought that the beta-blockers with a very slight ISA and a marked MSA, such as indenolol, was most suitable for the long-term treatment of essential tremor.
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PMID:Comparative studies on the effects of beta-adrenergic blockers in essential tremor. 289 95

1. beta-adrenoceptor blocking agents with intrinsic sympathomimetic activity (ISA) are characterized by lesser depression of cardiac performance during low levels of sympathetic stimulation than beta-adrenoceptor blocking agents lacking ISA. Studies of the effects of ISA on cardiac output and on the determinants of myocardial oxygen demand during submaximal exercise are described and distinct differences between beta-adrenoceptor antagonists with and without ISA emerge. 2. At doses which produce similar effects on maximal exercise heart rate, and resting and exercise systolic blood pressure, pindolol, a beta-adrenoceptor blocking agent with substantial ISA, allows a higher submaximal exercise cardiac output and submaximal heart rate X systolic blood pressure product than does propranolol, a beta-adrenoceptor antagonist without ISA. 3. These findings may have clinical relevance in specific groups of patients such as those with arterial hypertension, where the preservation of cardiac function may allow for a more physiologic exercise response. Implications in patients with coronary artery disease and chronic heart failure await further study.
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PMID:Cardiac effects of beta-adrenoceptor blockade with intrinsic sympathomimetic activity during submaximal exercise. 289 23

The possibilities for therapy in the field of severe cardiac insufficiency have been extended in recent years by the introduction of novel agents endowed with a positive inotropic action. These substances may be arranged in two large classes: sympathomimetic agents and "non sympathomimetic--non digitalis-like" inotropic agents. The stimulant action of noradrenaline, adrenaline and isoproterenol on beta-adrenergic myocardial receptors has been clearly demonstrated but the usefulness of these medicines is limited by their positive chronotropic and arrhythmogenic actions. Dopamine and dobutamine have proved to be very useful in the treatment of patients in intensive care units. However, the exclusively intravenous route of administration limits their importance to the medium or long term. Several compounds, which are active by the oral route, have been the subject of therapeutic trials for the short or medium term. The problems posed by their use result, in the first place, from an insufficient understanding of their mechanism of action. Some of them (pirbuterol, salbutamol, terbutaline, penoterol) seem to act preferentially on B2 adrenergic receptors and the haemodynamic effect results, in part or predominantly, from the vasodilator action which they cause. On the other hand, other agents (prenalterol, ICI 108-87) show a relative selectivity for B1 adrenergic receptors. Ibopamine exerts its action on B1 receptors and dopaminergic receptors. A second problem concerns the hypothetical character of their long term therapeutic activity. A major problem in the use of several of these sympathomimetic agents in chronic treatment is the appearance of a desensitization of the beta receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[New cardiotonic agents]. 293 98

The interaction between digoxin and the beta-sympathomimetic drug doxaminol was investigated in cats with acute heart failure induced by pentobarbital sodium. Doxaminol, 50 micrograms/kg X min, infused for 60 min caused a dose-dependent rise in dp/dtmax with little increase in heart rate. The maximum increase of 4.3 mHg/s was obtained after about 37 min. Digoxin, 10 micrograms/kg X min, and the combination of both drugs were infused until cardiac arrest. The maximum increase of dp/dtmax was observed after 29 min in both experiments; it was 5.7 mHg/s with digoxin alone and 7.3 mHg/s with the combination (p = 0.025). The combined infusion of epinephrine (0.3 micrograms/kg X min) plus digoxin (10 micrograms/kg X min) caused a maximal increase of dp/dtmax by 7.9 mHg/s. The cardiotoxic dose of digoxin was markedly reduced by epinephrine, not by doxaminol. The relevance of this difference to man cannot be assessed definitely because the ECG changes produced by digoxin in cats are different from those seen in man.
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PMID:Increase in the cardiotonic action and in the therapeutic margin of digoxin by the adrenergic beta-stimulant doxaminol in cats. 300 17

In the past few years an intense effort has been directed toward the development of new inotropic agents for the treatment of chronic cardiac failure. Traditionally, therapy of this disease has included treatment with digitalis glycosides, diuretics, sodium restriction and vasodilators. While digitalis has proven to be an effective inotropic agent, it possesses a low therapeutic index and many patients remain symptomatic or 'refractory' despite its inotropic effects. This review focuses on the pharmacokinetics and pharmacodynamics of newer inotropic agents that have been developed or which are currently undergoing investigation. Amrinone and milrinone are two bipyridine derivatives which have been shown to be effective in the short term treatment of cardiac failure. Milrinone is currently being evaluated for its long term efficacy. The mechanism of action of amrinone and milrinone appears to be unrelated to the cardiac glycosides and sympathomimetic agents, and they are rapidly and well absorbed following oral administration. The bioavailability of milrinone appears to be somewhat reduced in patients with chronic cardiac failure. The distribution of these drugs to extravascular tissues is very rapid; the volume of distribution suggests that they are not extensively bound to tissues. While the volume of distribution of amrinone appears to be unaffected by the presence of heart failure, that of milrinone appears to be somewhat enhanced. The major route of elimination of both drugs appears to be excretion into urine as unchanged drug. A substantial fraction of the amrinone dose, however, undergoes hepatic metabolism to many metabolites, including an N-acetyl derivative. Clearance of amrinone and milrinone is dramatically reduced in patients with chronic cardiac failure compared with normal volunteers, resulting in proportionate increases in the serum half-lives of these drugs. Studies examining the acute and chronic disposition of these agents in cardiac failure patients have not demonstrated changes in their pharmacokinetics secondary to improvements in cardiocirculatory function. Both drugs show strong correlations between mean improvements in haemodynamics and drug serum concentrations, although considerable intrapatient variability may exist. It is currently unclear as to whether the site for the pharmacological action of amrinone is pharmacokinetically distinguishable from plasma. Enoximone and its sulphoxide metabolite, piroximone, are two compounds currently undergoing investigation for the treatment of chronic cardiac failure.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The pharmacokinetics and pharmacodynamics of newer inotropic agents. 330 72

Dobutamine is a sympathomimetic amine that was designed as an inotropic agent for use in congestive heart failure. Clinically, dobutamine increases cardiac output by selectively augmenting stroke volume, and this is associated with a decrease in total peripheral vascular resistance that is mediated, in part, by reflex withdrawal of sympathetic tone to the vasculature. This hemodynamic profile of dobutamine makes the drug of value in the management of low output cardiac failure. The inotropic activity of dobutamine has previously been attributed to selective stimulation of myocardial beta 1-adrenoceptors. However, recent studies from a number of laboratories indicate that the mechanism of action of dobutamine is substantially more complex. Dobutamine has the capacity to stimulate beta 1-, beta 2-, and alpha 1-adrenoceptors in the cardiovascular system at doses that approximate those used clinically. It has recently been suggested that the inotropic activity of dobutamine results from combined beta 1- and alpha 1-adrenoceptor stimulation in the myocardium, and that this activity could explain, at least in part, the inotropic selectivity of the compound. Furthermore, in the vasculature, the beta 2-adrenoceptor-mediated vasodilatory effect of dobutamine is exactly offset by the alpha 1-adrenoceptor-mediated vasoconstrictor activity, such that net changes in blood pressure are minimal following the administration of dobutamine. It is concluded, therefore, that the hemodynamic profile of dobutamine in patients with congestive heart failure is derived from a unique and complex series of interactions with alpha- and beta-adrenoceptors in the cardiovascular system.
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PMID:The pharmacology of dobutamine. 331 Jun 40

The study of drug distribution in pregnancy was limited by ethical, technical and medico-legal considerations as samples of body fluids could only be taken at delivery. In recent times fetal blood samples have been taken with the fetoscope and will provide a new tool to monitor fetal concentrations and metabolic pathways. The advanced technology of ultrasound allows non invasive study of the fetal circulation and early experience of sympathomimetic drugs administered to the mother will be discussed. Auto immune disorders carry high perinatal wastage. New drugs have made reproductive life possible and when used prudently can improve maternal state and increase fetal salvage. The author has personally managed nearly 52 cases of systemic lupus erythematosus and 16 cases of idiopathic thrombocytopenic purpura. The use of steroids and low dosage aspirin therapy with elevated lupus anticoagulant levels will be described. Two cases of early hydrops in the fetus owing to heart failure due to supraventricular tachycardia were treated with digoxin given to the mother. The potential of therapeutic agents in fetal medicine will be discussed as it recognises the fetus as a patient and provides effective intra uterine therapy.
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PMID:Drugs in feto maternal medicine. 331 58

Treatment of heart failure comprises the use of diuretics, vasodilators and inotropic substances. Unloading of the heart and the circulation in hydropic states is classically achieved with diuretics. The retention of salt and water in chronic heart failure requires chronic treatment with diuretics. This mode of treatment is basic to all forms of hydropic heart failure. Inotropic substances such as digitalis glycosides, sympathomimetic amines or phosphodiesterase inhibitors have certain disadvantages: Inotropic stimulation increases energy demand of the working heart muscle. Most of the substances used today increase energy consumption inordinately, thereby decreasing economy of myocardial contraction. This aspect calls for caution in the application of these substances in chronic heart failure, although they seem indispensable (sympathomimetic amines) in acute hypotensive failure and shock. Digitalis glycosides, basically suited for longterm treatment, exert only mild inotropic effects. In addition inotropic stimulation brings with it arrhythmogenic effects. All inotropic substances can induce ventricular arrhythmias already at therapeutic levels. Vasodilating substances have found increasing acceptance as a particularly useful and safe group of drugs for the treatment of heart failure. Nitrates: With the different nitrate compounds and nitrate preparations an effective venodilation with preload reduction can safely be achieved. At higher doses, arteriolar also dilatation can be induced. Although tolerance may be a problem with chronic application, this can be avoided with prudent dosing. The strong venodilating property makes these drugs together with their rapid onset of action ideally suited for the treatment of acute heart failure with pulmonary congestion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Treatment of heart failure: status of therapy with vasodilator agents]. 343 15

Retrospective studies have shown that patients with severe chronic heart failure who receive long-term treatment with positive inotropic agents have a high mortality rate, but in the absence of controlled trials it remains unclear whether the high incidence of fatal cardiovascular events in these patients is related to treatment or to the severity of the underlying disease. Most of the evidence that suggests a detrimental effect of positive inotropic therapy on survival remains circumstantial. The pooling of data from long-term studies of patients after an acute myocardial infarction suggests that use of digitalis may be associated with an unfavorable effect on survival. The prolonged administration of intravenous or oral catecholamines is associated with a high mortality rate, which may not be seen in similar patients treated conventionally. The presence of intrinsic sympathomimetic activity appears to neutralize the benefits of beta-blockade during the first year after an acute myocardial infarction; treatment with such agents after the first year may increase mortality. Long-term treatment with phosphodiesterase inhibitors is associated with a high mortality rate, which exceeds that reported in earlier years with vasodilator therapy. Nevertheless, most of these studies of positive intropic agents were not performed to evaluate the issue of survival and did not randomly assign patients to treatment groups. Hence, we do not know that the patients entered into these studies were truly comparable to their proposed control groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Survival in congestive heart failure during treatment with drugs with positive inotropic actions. 355 3


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