Drugs online research references
Clin Physiol. 1981 Oct;1(5):461-9.
Central and peripheral haemodynamic effects of prenalterol in patients with coronary heart disease.
Svendsen TL, Carlsen JE, Hartling OJ, Trap-Jensen J.
The acute haemodynamic effects of prenalterol, a selective adrenergic beta-I-receptor agonist were studied in eight patients with coronary heart disease. Prenalterol was administered intravenously in four increasing doses to a cumulative dose of 5.6 mg. Fifteen minutes after the last dose of prenalterol two doses of the selective adrenergic beta-I-receptor antagonist metoprolol were administered intravenously to a cumulative dose of 17-5 mg. Ten minutes after each dose cardiac output, heart rate, arterial blood pressure, pulmonary artery pressure, systolic time intervals and forearm blood flow were determined. Haemodynamic effects of prenalterol: cardiac index and heart rate increased maximally by 38% and 39% respectively. Stroke index was increased by 6-9% after the first and second dose. Mean blood pressure was increased by 9.8 mmHg. Total peripheral resistance index was reduced by 19%. The mean pulmonary artery pressure decreased by 3.8 mmHg and pulmonary resistance index was reduced by 48%. Systolic time intervals were all reduced significantly after the second dose, which reflected the positive inotropic effects of prenalterol. Forearm blood flow increased by 29% and forearm vascular resistance was decreased by 20%. Haemodynamic effects of metoprolol: the haemodynamic changes induced by prenalterol were stepwise counteracted by metoprolol. After the second dose all the haemodynamic variables had returned to the control levels. It is concluded that prenalterol possesses a considerable positive inotropic as well as positive chronotropic effect on the myocardium. Both the chronotropic and inotropic effect of prenalterol was counteracted by metoprolol.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7199993&dopt=Abstract
Eur Heart J. 1993 Oct;14(10):1375-85.
The link between acute haemodynamic adrenergic beta-blockade and long-term effects in patients with heart failure. A study on diastolic function, heart rate and myocardial metabolism following intravenous metoprolol.
Andersson B, Lomsky M, Waagstein F.
Wallenberg Laboratory for Cardiovascular Research, Salgrenska Sjukhuset, University of Goteborg, Sweden.
The present study was performed to find possible mechanisms linking the early effects of beta-blockade with the observed long-term effects in patients with heart failure. In 57 patients with heart failure, 13 +/- 3.1 mg of metoprolol was given intravenously. The patients were investigated by invasive haemodynamics (n = 34), including collection of myocardial metabolic data during atrial pacing stress (n = 16), by radionuclide angiography during physiological atrial pacing (n = 13), and by a bedside evaluation (n = 10). Diastolic function, measured by early peak filling rate, followed changes in heart rate, but was similar when heart rate was held constant by atrial pacing before and after beta-blockade. Following beta-blockade and slower heart rates, diastolic filling volumes were redistributed to late diastole. Metoprolol induced a parallel decrease in coronary sinus flow and myocardial oxygen consumption. Myocardial oxygen consumption following beta-blockade decreased both during spontaneous rhythm (25 +/- 15 to 16 +/- 8.8 ml min-1; P = 0.006), and during atrial pacing stress (30 +/- 13 to 23 +/- 11 ml.min-1; P = 0.004). Cardiac index decreased owing to reduction of heart rate (2.3 +/- 1.0 to 1.9 +/- 0.64 l.min-1.m2; P = 0.0003), while left ventricular filling pressure was unchanged. Ejection fraction and ventricular volumes were unaltered following atrial pacing or beta-blockade. There was a reflex increase in noradrenaline concentration after beta-blockade injection (0.96 +/- 0.66 to 1.20 +/- 0.91 nmol.l-1; P = 0.002), whereas myocardial noradrenaline overflow was unchanged. There was a trend towards an increase in myocardial lactate consumption after beta-blockade administration during atrial pacing stress. It is suggested that the surprisingly good tolerability seen after acute administration of beta-blockers to patients with severe heart failure may be explained by prolongation of the diastolic filling phase, which outweighs the negative inotropic effects. The reduced myocardial metabolic demand may allow the failing myocardium to recover and explain the excellent long-term effect on heart function following beta-blockade treatment.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8262085&dopt=Abstract
J Hypertens Suppl. 1984 Dec;2(2):S89-92.
Contrasting renal haemodynamic responses to the angiotensin converting enzyme inhibitor enalapril and the beta-adrenergic antagonist metoprolol in essential hypertension.
O'Connor DT, Mosley CA, Cervenka J, Bernstein KN.
The individual target organ response to blood pressure reduction is an important criterion in the selection of appropriate antihypertensive therapy. We assessed both the renal and the systemic haemodynamic responses to antihypertensive monotherapy (five to seven weeks) with the angiotensin converting enzyme (ACE) inhibitor enalapril (n = 12), in contrast to the cardioselective beta-adrenergic blocker metoprolol (n = 11) in subjects with essential hypertension. Enalapril lowered systolic and diastolic blood pressure, and the fall in blood pressure was mediated haemodynamically by a 34% fall in systemic vascular resistance. In the kidney, glomerular filtration rate, renal plasma flow and renal blood flow were maintained by a 23% fall in renal vascular resistance. The disproportionate fall in systemic resistance versus renal resistance actually reduced the renal fraction of cardiac output. By contrast, metoprolol lowered predominantly diastolic blood pressure, with an associated 25% fall in cardiac output, without significant changes in overall systemic vascular resistance. In the renal circulation, renal perfusion was well maintained by a 20% fall in renal vascular resistance, perhaps at the efferent arteriole, without change in the renal fraction of cardiac output. Neither drug altered weight, plasma volume or total blood volume. Thus, each drug represents effective antihypertensive monotherapy, with a generally favourable, though different, renal haemodynamic profile, characterized by effective autoregulation of renal perfusion even in the face of a fall in perfusion pressure.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6100882&dopt=Abstract
online pharmacies ||
Hair Million herbal formula for hair loss and hair growth ||
Amoxicillin ||
Tramadol ||
Paxil ||
Rx Drugs USA, Prescription Drugs Online Pharmacy ||
Zithromax ||
online pharmacy ||
Antibiotics and prescription medications online literature ||
Antibiotics