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At least 415 records · Page 23Linked to original sources
PubMed1988

[Adrenergic therapy and vigilance: beta-2 sympathomimetic aerosols in asthma].

It has been established that the use of beta-2 sympathomimetic aerosols is a safe and efficacious treatment of asthma. Unexpected cases of sudden death amongst insufficiently-treated patients or patients who stopped their treatment are not linked with the use of these drugs. To assess the risk of possible "receptor desensitization" it is necessary to notify these accidents to the Committee on Safety of Drugs and to take into consideration the opposite results of further administration and termination of treatment.

Adrenergic beta-Agonists↗
PubMedDate not supplied

The influence of intrinsic sympathomimetic activity on regional left ventricular function; use of regional ejection fraction to demonstrate a beneficial action by pindolol over propranolol on hypokinetic segments.

In a previous report from our laboratory, visual assessment of wall motion in patients with coronary artery disease demonstrated no advantage for pindolol, a beta blocking agent with intrinsic sympathomimetic activity (ISA), over propranolol on impaired regional left ventricular (LV) function. In this study, we reanalyzed the radionuclide ventriculograms using a computer-assisted method of deriving regional ejection fraction. Use of normalized values allowed hypokinetic and normokinetic segments to be identified and examined separately. Pindolol (5-10 mg twice a day) was compared to propranolol (40-80 mg 4 times a day) in 23 patients using a randomized, crossover study design. Supine resting heart rate was reduced less (70 +/- 12 beats/min vs 63 +/- 10 beats/min, p less than 0.01) by pindolol; exercise heart rate was reduced equally by both agents. Derivation of normalized regional LV ejection fractions showed that 17 segments were hypokinetic at rest. Function of these segments increased (p less than 0.02) with pindolol. This improvement was not detected by visual assessment of regional wall motion. Thirty-seven segments were found to be hypokinetic during exercise and a significant (p less than 0.05) improvement in function occurred with pindolol and propranolol. In summary, derivation of normalized regional LV ejection fraction values allows the demonstration of significant improvement in resting LV function with pindolol, but not with propranolol in patients with regional dysfunction due to coronary artery disease. This advantage may provide a rationale for further evaluation of this agent in patients with more widespread ventricular dysfunction.

Angina Pectoris↗
PubMed1987

Treatment of general uterine spasm with a beta-sympathomimetic tocolytic, fenoterol hydrobromide (Partusisten).

Premature separation of the placenta is, in most cases, accompanied by tetania uteri. In this situation caesarean section is generally the right choice of treatment. The authors present five selected and carefully monitored cases where intravenous use of a beta-sympathomimetic drug (fenoterol) eliminated the uterine spasm and rhythmic uterine contractions developed. Accordingly, this therapy is a realistic alternative to caesarean section in the treatment of tetania uteri if the patient is in good general condition not necessitating emergency surgery.

Adult↗
PubMedDate not supplied

Colorimetric determination of sympathomimetic amines methyldopa and noradrenaline.

The chromogenic reagent p-dimethylaminocinnamaldehyde (PDAC) is introduced for the determination of the sympathomimetic amines methyldopa and noradrenaline. The method is based on measurement of the orange color developed when the alkaline solution of methyldopa and noradrenaline is allowed to react with PDAC at pH 5.0. The color developed obeys Beer's law in the concentration range 0.1-1.5 mL of 2 X 10(-3)M solution of noradrenaline and methyldopa. The results are compared with those obtained with another chromogenic reagent, p-dimethylaminobenzaldehyde (PDAB). Determinations on dosage forms of the drugs, using PDAC and PDAB reagents, agreed well with results of determinations by official pharmacopoeial methods.

Benzaldehydes↗
PubMed1985

Effects of a beta-sympathomimetic drug on the foetal and maternal cardiovascular system in a chronic sheep model.

The effects of the beta-sympathomimetic agent terbutalin (1-/3.5 dihydroxyphenyl/-allilaminoethane sulphonate) on maternal and foetal circulation were studied in 11 ewe at 110-130 days of pregnancy. None of them exhibited uterine contractions. Catheters were implanted in the carotid artery and jugular vein, together with four stainless steel electrodes on the limbs. Terbutalin was added intravenously in Ringer-lactate (5%) infusion (1 ml/min). The following maternal and foetal parameters were measured simultaneously: heart rate, central arterial pressure, blood glucose levels, ECG. Intravenous administration of 100 micrograms terbutalin resulted in a 19% increase of maternal and 10% enhancement of foetal heart rate. Maternal systolic blood pressure rose by 9%, whereas diastolic blood pressure fell by 7%. Maternal and foetal blood glucose levels was fairly constant during the entire experiment. In further six experiments terbutalin was administered into the foetal circulation (1 ml/3 min). The same effects on foetal heart rate and pulse pressure were observed as after injecting into the maternal circulation, however but the time necessary for the maximum action to develop was significantly shorter.

Animals↗
PubMed1980

Potentiative effects of alpha agonistic sympathomimetic amines on vasoconstriction by adrenergic nerve stimulation.

The effects of catecholamines and other sympathomimetic amines with alpha adrenergic activity on vasoconstriction were studied. Short ring segments were prepared from five rabbit blood vessels including the mesoduodenal, brachial, central ear and pulmonary lobar arteries and the saphenous vein. Constriction was elicited by electrical field stimulation of adrenergic neurons. This response was markedly potentiated in the mesenteric preparation by low concentrations of norepinephrine, epinephrine, phenylephrine, methoxamine, naphazoline and oxymetazoline. The potentiation occurred with amine concentrations not sufficient to elevate the spontaneous transmitter release or basal smooth muscle tone. Propranolol, cocaine and metanephrine did not prevent the potentiation. Isoproterenol and dopamine potentiated the response only in high concentrations and tyrosine was without an effect. An unidentified extraneuronal action was probably responsible for the potentiation. The mesenteric artery was unique for its marked potentiation as the brachial artery was potentiated only slightly and the other three vessels were inhibited by the alpha adrenergic agents in the constrictor response to stimulation.

Adrenergic alpha-Agonists↗
PubMed1983

Intrinsic sympathomimetic activity of the partial agonist prenalterol in relation to beta adrenoceptor interaction in various tissues, in vitro.

The intrinsic sympathomimetic activity (ISA) of prenalterol was studied in isolated tissues from different species, including tissues containing predominantly beta-1 adrenoceptors (cardiac preparations from cat, rabbit, rat and guinea pig) and tissues characterized by beta-2 adrenoceptor predominance (cat skeletal muscle and rat uterus). The ISA of prenalterol, varying between 0 and 94% in the various tissues, was found to be positively correlated to the stimulatory potency (-log EC50) of isoproterenol and prenalterol. In the cardiac preparations from the rabbit there was an interindividual variation in the ISA of prenalterol, which was also positively correlated to the stimulatory potency of the beta agonists. The density of beta adrenoceptors in the tissues studied correlated neither to the variable ISA of prenalterol nor to the -log EC50 values of isoproterenol or prenalterol. The affinities of isoproterenol and prenalterol for the beta adrenoceptors were subject to less variation than were the stimulatory potencies of the agonists. The degree of separation between the concentration-effect curves for beta adrenoceptor occupancy and mechanical performance, expressed as the ratios Kd/EC50 for both agonists, were positively correlated to the corresponding ISA of prenalterol in various tissues. However, a considerably steeper relationship between occupancy/potency ratio and ISA was seen with prenalterol than with isoproterenol. The present data suggest that the level of ISA of the partial agonist, prenalterol, depends upon the efficiency of signal transmission from the activated receptor to the final end-organ response. The separation between the concentrations of the full agonist, isoproterenol, required for receptor occupancy and response serves as an index of the efficiency of coupling between the stimulus, elicited by activation of the receptor, and the response.

Adrenergic beta-Agonists↗
PubMed1983

Anesthesiological problems related to the use of beta-sympathomimetic drugs for chronic and acute tocolysis.

Pregnant women treated with intravenous beta-sympathomimetics for acute or chronic tocolysis often show cardiovascular side-effects, mainly tachyarrhythmias, and electrolyte disorders, mainly hypokaliemia. Both create a potential hazard at the moment of induction of general anesthesia. For these patients one will use drugs exhibiting minimal hemodynamic side-effects and no oxytocic activity. Barbiturates as induction agent, and intravenous analgesics for maintenance of anesthesia after extraction of the neonate represent the safest solution. A short delay of ten minutes between administration of the beta-mimetic and induction of anesthesia avoids the coincidence of the maximal cardiovascular effects of the beta-mimetic with the stress of induction, and allows adequate preoxygenation of the patient.

Adrenergic beta-Agonists↗
PubMed1983

Haemodynamic consequences of intrinsic sympathomimetic activity in relation to changes in plasma renin activity and noradrenaline during beta-blocker therapy for hypertension.

The acute and long-term haemodynamic effects of pindolol, practolol, alprenolol, oxprenolol, acebutolol, penbutolol, metoprolol, atenolol, propranolol and timolol in patients with uncomplicated hypertension as reported in the literature were analysed. The long-term effects of these beta-adrenoceptor antagonists on plasma renin activity and the concentration of noradrenaline in plasma were also reviewed. In spite of the many pharmacological and physicochemical differences the drugs appeared to have a hypotensive effect of approximately equal magnitude. The degree of cardiodepression and the suppression of plasma renin activity as exerted by the different beta-blockers were inversely correlated with their pharmacologically defined degree of intrinsic sympathomimetic activity (ISA). The increments in vascular resistance acutely after administration of a beta-blocker are proportional to the degree of cardiodepression, suggesting that increased vasoconstrictor nerve activity mediated through the baroreflex had prevented an acute fall in arterial pressure in response to a given fall in cardiac output. After long-term therapy the inverse correlation between changes in cardiac output and changes in vascular resistance is shifted to a lower level of vascular resistance. Plasma renin activity and vascular resistance are inversely correlated during long-term beta-blocker therapy for hypertension. Consequently, the fall in vascular resistance underlying the hypotensive effect of beta-blockers cannot be explained by suppression of plasma renin activity. Thus, cardiodepression and renin suppression are not essential for the hypotensive effect of beta-adrenoceptor antagonists. The accessibility of the central nervous system to the different beta-blockers neither determines the time of onset of blood pressure reduction nor the magnitude of this effect. If it is neither the blockade of postsynaptic beta-adrenoceptors in the heart or on juxtaglomerular cells, nor the blockade of central beta-receptors that can be held responsible for the blood pressure lowering efficacy of beta-adrenoceptor antagonists, one is left with the remaining possibility that blockade of presynaptic beta-receptors underlies the vasodilator and antihypertensive action of these drugs. Changes in the concentrations of noradrenaline in plasma are compatible with this supposition, provided that changes in clearance of noradrenaline from plasma are taken into account.

Adrenergic beta-Antagonists↗
PubMed1980

[Occurrence of pulmonary oedemas without myocardial necroses under beta 2-sympathomimetic therapy with fenoterol (experimental investigations in the rabbit (author's transl)].

Experimental investigations in the rabbit were aimed at solving the question whether the development of a pulmonary oedema during tocolytic therapy with beta 2-sympathomimetics can be explained by hyperhydration, since myocardial necroses are not likely to be the cause of a pulmonary-oedema at the standard clinical dosage level. Fenoterol is infused over a period of 24 hours in combination with low (2.5 mgl/h) and high (30 ml/h) supply of liquid (isotonic solution, Sterofundin). Essential changes in the measured parameters occur only if the quantity infused is high. The following findings were established: 1. an increase in the liquid content of the lung and heart from 80 to 90%. 2. blood gas analysis revealed marked signs of a ventilatory disturbance, 3. histologically, the lungs showed partly massive changes pointing to the presence of an interstitial and intraalveolar oedema. Since no myocardial necroses can be histologically identified, the pulmonary insufficiency cannot be due to cardiac decompensation as a result of myocardial necroses.

Animals↗
PubMed1983

Pindolol--a new beta-adrenergic blocking agent with intrinsic sympathomimetic activity in the management of mild and moderate hypertension.

Pindolol, a well-tolerated noncardioselective beta-adrenergic blocking drug, effectively reduced blood pressure in patients with mild to moderate hypertension without causing orthostatic hypotension. In common with other beta-adrenergic blocking agents, pindolol blocked the normal increase in the standing pulse rate. The drug, however, did not decrease the supine pulse rate, a feature that can be interpreted as evidence of the postulated intrinsic sympathomimetic activity of pindolol.

Adolescent↗
PubMed1994

[Use of sympathomimetic agents in fetal atrioventricular heart block].

A healthy pregnant was referred at 34 weeks gestation because an obstetrical ultrasound examination had shown fetal bradycardia and nonimmune hydrops. The heart was anatomically normal but complete heart block was present with a ventricular rate of 22bpm and atrial of 101bpm. We injected isoproterenol by cordocentesis direct in the umbilical vein of the fetus and a significant increase into the ventricular and atrial rates were obtained. The direct therapy with sympathomimetic drugs is a simple technique and may save fetuses with complete heart block and hidrops.

Adult↗
PubMed1993

Influence of beta-blockade with beta-1-selectivity or intrinsic sympathomimetic activity on some metabolic responses to exercise.

Beta-blockers that are non-selective, beta-1-selective or possess intrinsic sympathomimetic activity (ISA) are thought to differ in their effects on serum potassium, glucose and lactate during exercise. In a randomized, double-blind, cross-over, placebo-controlled study, 21 healthy male volunteers took placebo, propranolol, pindolol and metoprolol on separate occasions. They were subsequently exercised using the same exercise protocol on each visit and serum levels of potassium, glucose and lactate determined before and after exercise. Only propranolol (non-selective beta-blocker with no ISA) was associated with significantly higher increases in serum potassium and glucose than placebo (p = 0.000). Increases in serum lactate levels with exercise were not significantly different between propranolol, pindolol (non selective blockers with ISA), metoprolol (beta-1-selective blocker with ISA) and placebo. Interference with metabolic responses to exercise associated with beta-blockade is modified by beta-1-selectivity and ISA amongst indigenous Kenyans.

Adrenergic beta-Antagonists↗
PubMed1993

Influence of beta-blockade with beta-1-selectivity or intrinsic sympathomimetic activity on some cardiorespiratory responses to exercise.

Possession of beta-1-selectivity and intrinsic sympathomimetic activity (ISA) by beta-adrenergic blocking drugs have been found to modify the effects of these drugs on heart rate, blood pressure and pulmonary airway resistance both at rest and during exercise. In a randomised, double-blind, cross-over, placebo-controlled trial, 21 healthy male volunteers took placebo, propranolol (non-selective with no ISA), metoprolol (beta-1-selective with no ISA) and pindolol (non-selective with ISA) on separate occasions prior to an exercise test using the same protocol each time. Heart rate, blood pressure and peak respiratory flow rate (PEFR) were measured before exercise and at exhaustion. No significant differences in percentage increase in heart rate after exercise were detected between placebo and all the three beta-blockers. All three drugs were associated with significantly lower percentage increases in systolic blood pressure with exercise compared to placebo; with metoprolol and propranolol causing lower increases than pindolol. The index of myocardial oxygen consumption, MVO2, was highest with pindolol. PEFR was reduced most by propranolol. Possession of beta-1-selectivity and ISA by beta-blocking drugs modifies their effects on cardio-respiratory responses to exercise amongst indigenous Kenyans.

Adrenergic beta-Antagonists↗