ATC Group: C07A Beta blocking agents

Acebutolol is a beta adrenoceptor antagonist which is cardioselective, i.e. acts preferentially on beta-1 adrenergic receptors in the heart. Its principal effects are to reduce heart rate especially on exercise and to lower blood pressure in hypertensive subjects.

Alprenolol is a non-selective beta blocker as well as a 5-HT1A and 5-HT1B receptor antagonist, used in the treatment of angina pectoris.

Atenolol is a beta-blocker which is beta₁-selective, (i.e. acts preferentially on beta₁-adrenergic receptors in the heart). Atenolol is without intrinsic sympathomimetic and membrane-stabilising activities and as with other beta-blockers, has negative inotropic effects.

Betaxolol is a cardioselective Beta₁ receptor blocker which, when applied topically to the eye, lowers intraocular pressure. It is thought to produce this effect by reducing the rate of production of aqueous humour.

Bisoprolol is a potent highly beta₁-selective-adrenoceptor blocking agent, lacking intrinsic stimulating and without relevant membrane stabilising activity.

Carteolol is a non-selective beta-adrenergic blocking agent with associated intrinsic sympathomimetic activity (ISA) and without significant membrane stabilizing activity. Carteolol reduces normal and elevated intraocular pressure whether or not accompanied by glaucoma.

Carvedilol is a vasodilatory non-selective beta-blocker, which reduces the peripheral vascular resistance by selective alpha₁-receptor blockade and suppresses the renin-angiotensin system through non-selective beta-blockade. Plasma renin activity is reduced and fluid retention is rare.

Celiprolol is a vasoactive beta-l selective adrenoceptor antagonist with partial beta-2 agonist activity indicated in mild to moderate hypertension. The beta-2 agonist activity is thought to account for its mild vasodilating properties. It lowers blood pressure in hypertensive patients at rest and on exercise.

Esmolol is a beta-selective (cardioselective) receptor blocking agent. At therapeutic doses esmolol has no significant intrinsic sympathicomimetic activity (ISA) or membrane stabilising activity.

Labetalol lowers the blood pressure by blocking peripheral arteriolar alphaadrenoceptors thus reducing peripheral resistance, and by concurrent betablockade, protects the heart from reflex sympathetic drive that would otherwise occur.

Landiolol is a highly selective beta-1-adrenoreceptor antagonist that inhibits the positive chronotropic effects of the catecholamines adrenaline and noradrenaline on the heart, where beta-1-receptors are predominantly located. Landiolol, as other beta-blockers, is thought to reduce the sympathetic drive, resulting in reduction in heart rate, decrease in spontaneous firing of ectopic pacemakers, slowing the conduction and increase the refractory period of the AV node.

Metoprolol is a cardioselective beta-adrenergic blocking agent. It has a relatively greater blocking effect on beta₁-receptors (ie those mediating adrenergic stimulation of heart rate and contractility and release of free fatty acids from fat stores) than on beta₂-receptors, which are chiefly involved in broncho and vasodilation.

Nadolol is a synthetic nonselective beta-adrenergic receptor blocking agent. Clinical pharmacology studies have demonstrated beta-blocking activity by showing (1) reduction in heart rate and cardiac output at rest and on exercise, (2) reduction of systolic and diastolic blood pressure at rest and on exercise, (3) inhibition of isoproterenol-induced tachycardia, and (4) reduction of reflex orthostatic tachycardia.

Nebivolol is a racemate of two enantiomers, SRRR-nebivolol (or d-nebivolol) and RSSS-nebivolol (or l-nebivolol). It is a competitive and selective beta-receptor antagonist and it has mild vasodilating properties due to an interaction with the L-arginine/nitric oxide pathway.

Oxprenolol is a non-selective, lipophilic betablocker exerting a sympatholytic effect and displaying mild to modest partial agonistic activity (PAA), also known as intrinsic sympathomimetic activity (ISA). Oxprenolol decreases cardiac impulse formation in the sinus node with resultant slowing of the sinus rate.

Penbutolol is a β-1, β-2 (nonselective) adrenergic receptor antagonist. The β-blocking potency of penbutolol is approximately 4 times that of propranolol. Penbutolol is used for the management of mild to moderate arterial hypertension, alone or in combination with other antihypertensive agents.

Pindolol is a potent beta-adrenoceptor antagonist (beta-blocker) with uses similar to those of propranolol. It is classified as non cardioselective. It blocks both B₁- and B₂-adrenoceptors for more than 24 hours after administration. It has negligible membrane-stabilising activity. Pindolol exhibits low cardiodepressant activity at therapeutic dose.

Propranolol is a competitive antagonist at both beta, and beta₂-adrenoceptor, but has membrane stabilising activity at concentrations exceeding 1-3mg/litre, though such concentrations are rarely achieved during oral therapy. Competitive beta-blockade has been demonstrated in man by a parallel shift to the right in the dose-heart rate response curve to beta-agonists such as isoprenaline.

D,l-sotalol is a non-selective hydrophilic β-adrenergic receptor blocking agent, devoid of intrinsic sympathomimetic activity or membrane stabilizing activity. Sotalol has both beta-adrenoreceptor blocking (Vaughan Williams Class II) and cardiac action potential duration prolongation (Vaughan Williams Class III) antiarrhythmic properties.

Timolol is a non-selective beta-adrenergic receptor blocking agent that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anaesthetic activity. Timolol reduces intra-ocular pressure, whether or not this is associated with glaucoma.