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Related to beta-blockers: alpha-blockers


A class of medication used to block the cellular response to chemicals normally present in the body.


; beta-adrenoceptor-blocking drugs; β-blockers agents that block beta- adrenoceptors of heart, peripheral vasculature, bronchi, pancreas and liver; often administered in conjunction with thiazide diruetics; cardiovascular effects: slow heart rate, reduce blood pressure; relieve symptoms of glaucoma; exacerbate Raynaud's; bronchial effects: exacerbate asthma; pancreatic effects: tend to impaired glucose tolerance and mask early symptoms of hypoglycaemia; hepatic effects: additive toxic effect with local anaesthetic (see also Table 1)
Table 1: Effects of stimulation of alpha, beta and dopamine receptors
ReceptorActionStimulating drug
Alpha-1 (α1); postsynapticVasoconstriction; positive inotropism; antidiuresisAdrenaline +
Noradrenaline +++
Alpha-2 (α2); presynapticVasodilatation; inhibition of noradrenaline releaseAdrenaline +
Noradrenaline +++
Dopamine +
Alpha-2 (α2); postsynapticConstriction of coronary arteries; promotion of salt and water excretionAdrenaline +
Noradrenaline +++
Dopamine +
Beta-1 (β1); postsynapticPositive inotropism; chronotropism; renin releaseAdrenaline ++
Noradrenaline ++
Isoprenaline ++
Dopamine +
Beta-2 (β2); presynapticNoradrenaline release accelerated; positive inotropism; chronotropismAdrenaline +
Isoprenaline +++
Beta-2 (β2); postsynapticVasodilatation; relaxation of bronchial smooth muscleAdrenaline +
Isoprenaline +++
Dopamine1; postsynapticVasodilatation; diuresisDopamine ++
Dopamine1; presynapticInhibits noradrenaline releaseDopamine +

Plus signs indicate degree of effect.

References in periodicals archive ?
Beta-blocker therapy doesn't reduce all-cause mortality, cardiovascular mortality cardiovascular hospitalization, or stroke in patients with heart failure who also have atrial fibrillation, Di-pak Kotecha, Ph.
Effective heart rate control for the whole perioperative period was achieved in 29 (9%) patients on perioperative beta-blockers and 10 (3%) patients not on perioperative beta-blockers, P=0.
Patients on beta-blockers were significantly older (51 years vs.
Beta-blockers, which are FDA approved for heart problems and hypertension, improve performance by reducing the physiological signs of stress.
Despite the fact that blood pressure was lowered to exactly the same extent as with diuretics, beta-blockers conferred no morbidity or mortality benefits (1).
In a consensus report published in February in the American Journal of Cardiology, doctors recommend most patients be treated with ACE inhibitors and beta-blockers in combination with commonly used digitalis and diuretics.
of McMaster University, an electrophysiologist-cardiologist, commented: "I believe that beta-blockers have only modest effects on prevention of serious ventricular arrhythmias, but in the Aleong et al study, patients with the higher activity beta-1 receptor genetic variant (389 arginine homozygous) had a significant (by 74%, p = 0.
SAN DIEGO--The use of beta-blockers by patients with advanced chronic kidney disease was not associated with a lower risk of all-cause mortality or initiation of chronic dialysis, results from a large study demonstrated.
Washington, Jan 20 (ANI): A new study has shown that beta-blockers in combination with certain anti-hypertensive drugs can significantly reduce blood pressure in hypertension patients.
Start-Up Developing Bone Beta-Blockers to Treat Osteoporosis Featured at TechCoire's June 3-4 Investor Conference, UC Davis' Mondavi Center
A number of independent organisations, such as the UK National Institute for Health and Clinical Excellence (NICE), working with the British Hypertension Society, have recommended that beta-blockers should no longer be the preferred initial therapy for hypertension, and that a calcium-channel-blocker or thiazide-type diuretic should be the first choice for initial therapy in hypertensive patients ages 55 or over, or in black patients of any age.