Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Orthostatic dysregulation (OD), originally a German-Scandinavian term partially corresponding to an Anglo-American concept of sympathotonic orthostatic hypotension, is characterised by altered cardiovascular control on standing, and its clinical features include dizziness, palpitation and, occasionally, orthostatic hypotension. The symptomatology suggests presence of cardiovascular adrenoceptor dysfunction, although the aetiology of OD has not been elucidated. The above situation prompted us to investigate autonomic nervous function in OD. The subjects were 8 patients with OD (20 +/- 2 years old; mean +/- SD), all of them fulfilled the diagnostic criteria accepted in Japan, and 6 healthy controls (17 +/- 3 years old). Noradrenaline and isoproterenol infusion tests and conventional haemodynamic functional tests (70 degrees passive head-up tilt, cold pressor test, Valsalva manoeuvre and Aschner's eye-ball pressure test) were carried out upon the subjects under the continuous measurement of blood pressure, pulse rate and respiration. Plasma vasoactive substances (noradrenaline, adrenaline, arginine-vasopressin and renin activity) were also determined in supine position and at 15 minutes after the 70 degrees passive head-up tilt. In noradrenaline infusion test, different doses (0.01 microgram/kg, 0.02 microgram/kg, 0.05 microgram/kg and 0.1 microgram/kg) of noradrenaline were administered by means of intravenous bolus injection, and a degree of subsequent rise in blood pressure was used as an index for the cardiovascular alpha-adrenoceptor sensitivity. In isoproterenol infusion tests cardiovascular beta 1- and beta 2-adrenoceptor sensitivities were assessed, respectively, by a degree of an increase in pulse rate and a degree of a fall in blood pressure following bolus injection of the drug (0.001 microgram/kg, 0.002 microgram/kg, 0.005 microgram/kg and 0.01 microgram/kg).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Cardiovascular alpha- and beta-adrenoceptor sensitivities in orthostatic dysregulation]. 216 87

The antihypertensive efficacy of bevantolol, a selective beta 1-adrenoreceptor antagonist, was evaluated in 17 patients with essential hypertension, using continuous ambulatory intraarterial blood pressure (BP) monitoring. The study compared a twice-daily regimen (titrated dose of 200 to 600 mg/day) with the same amount given in a single daily dose. Within-patient comparisons of mean hourly systolic and diastolic BPs and heart rate showed a highly significant effect with twice-daily therapy (p less than 0.001) for all of the 24 hours. Similar significant results were obtained with a single morning dose. There was no difference between the pattern or extent of BP reduction with the 2 regimens. The decrease in BP after bevantolol persisted during the physiologic tests (rest, tilt, isometric and dynamic exercise). Four patients developed minor side effects with the single morning dose, and only 1 patient with the twice-daily regimen. These effects included tiredness, fatigue and dizziness. Unlike pure beta-blocking agents, bevantolol controlled the early morning increase in BP, lending support to the belief that it possesses vasodilatory properties in addition to beta blockade. These results suggest that bevantolol may be useful as first-line therapy in a once-daily dosage for the treatment of essential hypertension.
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PMID:Once- and twice-daily bevantolol for systemic hypertension using 24-hour ambulatory intraarterial blood pressure recording. 287 95

During the intervening years since metoprolol was first reviewed in the Journal (1977), it has become widely used in the treatment of mild to moderate hypertension and angina pectoris. Although much data have accumulated, its precise mechanisms of action in these diseases remain largely uncertain. Optimum treatment of hypertension and angina pectoris with metoprolol is achieved through dose titration within the therapeutic range. It has been clearly demonstrated that metoprolol is at least as effective as other beta-blockers, diuretics and certain calcium antagonists in the majority of patients. Although a twice daily dosage regimen is normally used, satisfactory control can be maintained in many patients with single daily doses of conventional or, more frequently, slow release formulations. Addition of a diuretic may improve the overall response rate in hypertension. Several controlled trials have studied the effects of metoprolol administered during the acute phase and after myocardial infarction. In early intervention trials a reduction in total mortality was achieved in one moderately large trial of prolonged treatment, but in another, which excluded patients already being treated with beta-blockers or certain calcium antagonists and where treatment was only short term, mortality was significantly reduced only in 'high risk' patients. Overall results with metoprolol have not demonstrated that early intervention treatment in all patients produces clinically important improvement in short term mortality. Thus, the use of metoprolol during the early stages of myocardial infarction is controversial, largely because of the requirement to treat all patients to save a small number at 'high risk'. This blanket coverage approach to treatment may be more justified during the post-infarction follow-up phase since it has been shown that metoprolol slightly, but significantly, reduces the mortality rate for periods of up to 3 years. Metoprolol is generally well tolerated and its beta 1-selectivity may facilitate its administration to certain patients (e.g. asthmatics and diabetics) in whom non-selective beta-blockers are contraindicated. Temporary fatigue, dizziness and headache are among the most frequently reported side effects. After a decade of use, metoprolol is well established as a first choice drug in mild to moderate hypertension and stable angina, and is beneficial in post-infarction patients. Further study is needed in less well established areas of treatment such as cardiac arrhythmias, idiopathic dilated cardiomyopathy and hypertensive cardiomegaly.
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PMID:Metoprolol. An updated review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy, in hypertension, ischaemic heart disease and related cardiovascular disorders. 294 80

Carvedilol competitively blocks beta 1, beta 2 and alpha 1 receptors. The drug lacks sympathomimetic activity and has vasodilating properties that are exerted primarily through alpha 1-blockade. Animal models indicate that carvedilol confers protection against myocardial necrosis, arrhythmia and cell damage caused by oxidising free radicals, and the drug has no adverse effects on plasma lipid profiles. Recent data have confirmed the antihypertensive efficacy of carvedilol in patients with mild to moderate essential hypertension. Carvedilol has similar efficacy to other beta-blocking agents, calcium antagonists, ACE inhibitors and hydrochlorothiazide. Carvedilol also improves exercise tolerance and ischaemic symptoms in patients with stable angina pectoris. Significant reductions in serious cardiac events after acute myocardial infarction and in frequency and severity of ischaemic events in patients with unstable angina have also been demonstrated. Interest in the use of carvedilol in patients with congestive heart failure (CHF) has culminated in the publication of a cumulative analysis of data from 1094 patients with mild to severe CHF who participated in the US Carvedilol Heart Failure Study Program (4 trials). After a median follow-up of 6.5 months, a significant overall reduction in mortality relative to placebo (3.2 vs 7.8%) was revealed in patients who had received carvedilol 6.25 to 50 mg twice daily (plus diuretics and ACE inhibitors). All-cause mortality, risk of hospitalisation for cardiovascular reasons and hospitalisation costs were also reduced significantly (by 65, 28% and 62%, respectively) in these trials. In addition, the Australia and New Zealand Heart Failure Research Collaborative Group showed a 26% reduction in the combined risk of death or hospitalisation with carvedilol 12.5 to 50 mg/day relative to placebo after a mean 19-month follow-up period in 415 patients with CHF (relative risk 0.74). Adverse events with carvedilol appear to be less frequent than with other beta-blocking agents, are dosage-related and are usually seen early in therapy. Events most commonly reported are related to the vasodilating (postural hypotension, dizziness and headaches) and the beta-blocking (dyspnoea, bronchospasm, bradycardia, malaise and asthenia) properties of the drug. Carvedilol appears to date to have little effect on the incidence of worsening heart failure. Concomitant administration of carvedilol with some medications requires monitoring. Carvedilol is therefore likely to have a beneficial role in the management of controlled CHF, but further clinical studies are required to show the place of beta-adrenoceptor blocking therapy in general in this indication, and the position of carvedilol relative to other similar agents. Carvedilol is also confirmed as effective in the management of mild to moderate hypertension and ischaemic heart disease.
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PMID:Carvedilol. A reappraisal of its pharmacological properties and therapeutic use in cardiovascular disorders. 921 Oct 87

Nebivolol is a new selective beta 1-adrenergic blocking agent, that possesses a peculiar pharmacodynamic profile and an original chemical structure, by which it differs from traditional beta 1-blockers. Nebivolol is a racemic mixture of two enantiomers in equal ratios. It is endowed with a highly selective beta 1-blocking activity, and does not show an intrinsic sympathomimetic activity. Nebivolol is endowed with peripheral vasodilating properties mediated by the modulation of the endogenous production of nitric oxide. It does not significantly decrease airway conductance compared with atenolol and propranolol. Nebivolol does not compromise the left ventricular function, but it may increase stroke volume, and does not reduce heart inotropism during exertion. Nebivolol is quite safe and is well tolerated, also when compared to traditional beta-blockers. The most common adverse effects are dizziness, headache and fatigue. Owing to its combined dual mechanism of action, nebivolol leads to a unique haemodynamic and therapeutic profile by which it may be advantageous in essential hypertension, ischaemic heart disease and congestive heart failure.
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PMID:Pharmacology of nebivolol. 999 Jun 50

Controlled clinical trials, performed in more than 16,000 patients to date, have consistently shown the beneficial effects of long-term beta-blocker therapy in patients with chronic heart failure. However, it is not clear whether this represents a class effect or it is specific only to some agents. Beneficial effects on the prognosis of the patients with mild to moderate heart failure have been shown with metoprolol, bisoprolol, and carvedilol. However, these beta-blockers differ in their pharmacological characteristics. Metoprolol and bisoprolol are selective for beta 1-adrenergic receptors and are devoid of ancillary properties. Carvediol, at doses of 50 mg daily, blocks all beta 1-, beta 2-, and alpha 1- adrenergic receptors, and has associated antiproliferative and antioxidant activities. These differences cause a different acute hemodynamic response with a reduction in cardiac output and a tendency to a rise in pulmonary wedge pressure with selective agents and no change in cardiac output and a slight decrease in pulmonary pressures with carvedilol. Accordingly, when the therapy is started, the most frequent side effects are worsening heart failure with metoprolol and bisoprolol and hypotension and dizziness with carvedilol. It is still controversial whether these differences may also influence the long-term effects of therapy. Differently from selective beta-blockers, carvedilol does not upregulate beta 1-receptors, blocks all adrenergic receptors, decreases cardiac norepinephrine release, thus providing a more comprehensive blockade of the cardiac adrenergic drive. These properties have caused a larger increase in LV function and a lack of improvement in maximal exercise capacity with carvedilol, compared to selective beta-blockers. It is however, unclear whether these differences may also influence the patients' outcome.
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PMID:[New and old beta-blockers in the treatment of heart failure]. 1188 45

Nebivolol is a lipophilic beta 1-blocker. It is devoid of intrinsic sympathomimetic or membrane stabilising activity but appears to have nitric oxide-mediated vasodilatory effects. Nebivolol 5 mg once daily is well tolerated in patients with hypertension. Adverse events are infrequent, transient and mild to moderate. Those reported most often include headache, fatigue, paraesthesias and dizziness. Several studies reported no signs of orthostatic hypotension with Nebivolol.
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PMID:[Nebivolol treatment in essential arterial hypertension]. 1209 33