Beta-blockers with intrinsic sympathomimetic activity

Zimlichman R, Krauss S, Paran E. Muscle cramps induced by beta-blockers with intrinsic sympathomimetic activity properties a hint of a possible mechanism. Arch Intern Med 1991 151(5) 1021. 

Beta blockers without intrinsic sympathomimetic activity (eg, metoprolol, propranolol, atenolol) are effective therapeutic adjuncts in the management of thyrotoxicosis since many of these symptoms mimic those associated with sympathetic stimulation. Propranolol has been the 3 blocker most widely studied and used in the therapy of thyrotoxicosis. Beta blockers cause clinical improvement of hyperthyroid symptoms but do not typically alter thyroid hormone levels. Propranolol at doses greater than 160 mg/d may also reduce T3 levels approximately 20% by inhibiting the peripheral conversion of T4 to T3. 

Beta blockers without intrinsic sympathomimetic activity are effective therapeutic adjuncts in the management of thyrotoxicosis since many of these symptoms mimic those associated with... 

Prototype drug, but many other beta blockers are used in HTN (see ANS section, Chapter 3, for specifics on cardloselective drugs and those with intrinsic sympathomimetic activity [ISA]). All appear to be equally effective with respect to HTN. 

It is a nonselective beta blocker with marked intrinsic sympathomimetic activity. It has advantage over propranolol that it produces less bradycardia and rebound hypertension. Oxprenolol resembles propranolol and is short acting with mild intrinsic sympathomimetic activity. Alprenolol is similar to pindolol and oxprenolol. 

Imhof P. The significance of betal-beta2-selectivity and intrinsic sympathomimetic activity in beta-blockers, with particular reference to antihypertensive treatment. Adv Clin Pharmacol 1976 11 26-32. 

In the treatment of hypertension, a major use of beta-blockers is in combination with hydralazine. The direct vasodilators bring about reflex cardiac stimulation, and beta-blockers prevent these adverse effects (see also Figure 67). Beta-blockers also reduce blood pressure by exerting a central effect or a peripheral action, or both, which decreases renin activity. Metoprolol and atenolol are beta selective, and they are safer agents in patients with asthma, diabetes mellitus, or low-renin hypertension. Some beta-blocking agents such as pindolol have intrinsic sympathomimetic activity and may be used in the treatment of pronounced bradycardia (sick sinus syndrome). Unlike propranolol, metoprolol is not a very lipid-soluble... 

I. Pharmacology. Esmolol is a short-acting, IV, cardioselective beta-adrenergic blocker with no intrinsic sympathomimetic or membrane-depressant activity. In usual therapeutic doses, it causes little or no bronohospasm in patients with asthma. Esmolol produces peak effects within 6-10 minutes of administration of an intravenous bolus. It is rapidly hydrolyzed by red blood cell esterases, with an elimination half-life of 9 minutes therapeutic and adverse effects disappear within 30 minutes after the infusion is discontinued. 

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