Cardioselective beta-blockers

Nonselective beta-blockers may delay recovery from hypoglycemic episodes and mask their signs/symptoms. Cardioselective agents may be alternatives, ay sometimes be followed by hyperglycemia. ... 

Propranolol was the first blocker shown to be effective in hypertension and ischemic heart disease. Propranolol has now been largely replaced by cardioselective blockers such as metoprolol and atenolol. All B-adrenoceptor-blocking agents are useful for lowering blood pressure in mild to moderate hypertension. In severe hypertension, blockers are especially useful in preventing the reflex tachycardia that often results from treatment with direct vasodilators. Beta blockers have been shown to reduce mortality after a myocardial infarction and some also reduce mortality in patients with heart failure they are particularly advantageous for treating hypertension in patients with these conditions (see Chapter 13). 

Currently, a number of beta blockers are used clinically the selection of a specific agent depends on factors such as cardioselectivity, duration of action (half-life), and several other ancillary properties of each drug.110 Certain beta blockers, for instance, produce added effects such as mild peripheral vasodilation or stabilization of cardiac membranes that can be beneficial in treating certain cardiovascular condi-... 

Acebutolol (Sectral). Acebutolol is described as a relatively cardioselective beta blocker that tends to bind preferentially to beta-1 receptors at low doses, but binds to both types of beta receptors as the dosage increases. This drug also exerts mild to moderate intrinsic sympathomimetic activity, which means that acebutolol not only blocks the beta receptor from... 

Metoprolol (Lopressor, Toprol-XL). Metoprolol is considered a cardioselective beta blocker and has been approved for treating hypertension, preventing angina pectoris, and preventing myocardial reinfarction. As an antihypertensive and antianginal, metoprolol is usually administered orally. In the prevention of reinfarction, metoprolol is initiated by intravenous injection and then followed up by oral administration. 

Beta blockers that bind to both beta-1 and beta-2 receptors (nonselective agents, see Table 20-2) may induce bronchoconstriction in patients with asthma or similar respiratory problems. These patients should be given one of the more cardioselective beta antagonists, such as atenolol (Tenormin) or metoprolol (Lopressor, others). Beta blockers may also produce excessive cardiac depression in individuals with certain types of cardiac disease. Beta blockers are generally well tolerated in most patients, however, and major problems are infrequent. 

Anemia due to chronic renal failure Cardioselective beta-blocker Estrogen... 

CENTRALLY ACTING ANTI HYPERTENSIVES BETA-BLOCKERS Risk of withdrawal t BP (rebound t BP) with clonidine and possibly moxonidine Withdrawal of clonidine, and possibly moxonidine, is associated with t circulating catecholamines beta-blockers, especially non-cardioselective ones, will allow the catecholamines to exert an unopposed alpha action (vasoconstriction) Do not withdraw clonidine or moxonidine while a patient is taking beta-blockers. Withdraw beta-blockers several days before slowly withdrawing clonidine and moxonidine... 

BETA-BLOCKERS VENLAFAXINE T plasma concentrations and efficacy of metoprolol, propranolol and timolol Venlafaxine inhibits CYP2D6-mediated metabolism of metoprolol, propanolol and timolol Monitor PR and BP at least weekly watch for metoprolol toxicity (in particular, toss of its cardioselectivity) and propanolol toxicity... 

Although atenolol, a hydrophihc cardioselective beta-adrenoceptor antagonist with no partial agonist activity, is generally regarded as one of the safest beta-blockers, severe adverse effects are occasionally reported. These include profound hypotension after a single oral dose (1), organic brain syndrome (2), cholestasis (3), and cutaneous vascuhtis (4). 

Althongh beta-blockers have been available for many years, new members of this class with novel pharmacological profiles continne to be developed. These new drugs are claimed to have either greater cardioselectivity or vasodUatory and beta2-agonist properties. The claimed... 

A 60-year-old man with open-angle glaucoma developed an allergic contact conjunctivitis and dermatitis from carteolol, a topical non-cardioselective beta-blocker (149). He had extensive cross-reactivity to other topical beta-blockers, such as timolol and levobunolol. Cross-reactivity among different beta-blockers is possibly due to a common lateral aliphatic chain. 

Beta-blockers that are available as eye-drops include timolol, metipranolol, and levobunolol, which are non-selective betai- and beta2-adrenoceptor antagonists, and betaxolol, a relatively cardioselective betai-adrenoceptor antagonist. Although selective betai-blockers are less likely to precipitate bronchospasm, this and other systemic effects can nevertheless occur (SED-12,1200). 

Bevantolol, a hydrophilic cardioselective beta-blocker with membrane-stabilizing activity, may have a higher incidence of fatigue, headache, and dizziness than atenolol or propranolol (1,2). 

Desche P, Cournot A, Duchier J, Prost JF. Airway response to salbutamol and to ipratropium bromide after non-selective and cardioselective beta-blocker. Eur J Clin Pharmacol 1987 32(4) 343-6. 

Sigmoid Emax Model Jonkers and colleagues [80] studied the pharmacodynamics of racemic metoprolol, a cardioselective beta-blocker, and the active S-isomer in extensive metabolizers (EMs) and poor metabolizers (PMs). The drug effect studied was the antagonism by metoprolol of terbutaline-induced hypokalemia (abnormally low potassium concentration in the blood). The pharmacodynamic interaction was described by a sigmoidal function for competitive antagonism based on the earlier work of Holford and Sheiner [81] ... 

Salpeter SR, Ormiston TM, Salpeter EE. Cardioselective beta-blockers in patients with reactive airway disease A meta-analysis. Ann Intern Med 2002 137 715-725. 

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

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