Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002962 (angina)
 21,142 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sixteen male patients with typical angina pectoris secondary to coronary atherosclerosis performed two daily standardized exercise tests during two consecutive days. Three hours before each exercise they received placebo or 400 mg practolol administered orally in double-blind fashion in order to complete a cross-over design. Practolol significantly prolonged the exercise duration by 30.6% and delayed the appearance time of ischaemic electrocardiographic changes by 67.7%. Maximal heart rate, systolic pressure, and pressure-rate product were also reduced after medication. In order to investigate further the effects of this beta blocking agent, myocardial function and metabolism at rest and during supine exercise were assessed in 12 male patients with coronary artery disease before and after practolol 30 mg, iv. At rest, practolol produced a decrease in tension-time index (18%), cardiac index (17%), heart rate (10%), and stroke index (7%). A significant reduction was also observed in resting stroke work index (14%) and systolic and mean aortic pressure (6%). Left ventricular end-diastolic pressure remained unchanged. During supine exercise, only time-tension index (12%), heart rate (12%), and cardiac index (10%) were significantly reduced after the beta blocking agent. Practolol did not significantly change the arterial glucose, lactate, inorganic phosphate, potassium, calcium, magnesium, pH, PCO2, or PO2. The beta blocking agent did not modify the myocardial extraction of any of these substrates at rest or during exercise. In the dosage used in both studies, practolol significantly improved the exercise tolerance and reduced the ischaemic manifestations. The efficacy of practolol in angina pectoris may result mostly from its ability to decrease heart rate and systolic pressure during exercise.
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PMID:Effects of practolol on exercise tolerance and cardiac haemodynamics and metabolism in patients with coronary artery disease. 125 93

The concept of two patterns of catecholamine activity was first described at the turn of the century by Langely and Dale. In the late 1940s, Ahlquist conceptualized the alpha- and beta-blocking actions of catecholamines. Sir James Black's research in the 1950s led to the introduction of pronethalol and then of propranolol into the therapeutics of angina and arrhythmias. Early beta-receptor blocking compounds were noted not only to be competitive inhibitors of the beta receptor but to have a direct depressant, membrane-stabilizing action. Later compounds, such as pindolol, were noted to have partial agonist activity. Practolol, metoprolol, atenolol, and similar "cardioselective", or beta-selective, drugs were subsequently described. Agents that combine beta blockade with alpha blockade or vasodilator action have been developed recently. There are various therapeutically advantageous pharmacodynamic differences among the beta-blocking drugs, such as less effect of beta 1-selective drugs on bronchial smooth muscle. Lipid solubility, systemic bioavailability, first-pass liver metabolism, renal excretion, and brain penetration are pharmacokinetic properties that further distinguish one agent from another. After the initial predicted therapeutic uses, beta-blocking drugs were used in hypertension and subsequently have been applied in a wide range of cardiovascular conditions. Recent work clearly demonstrating a cardioprotective effect in the post-myocardial infarction period is a major reason that use of the agents is likely to remain high.
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PMID:Beta-blockage therapy and cardiovascular disease. Past, present, and future. 289 64