Beta-blocker choice

Figure II-4-11 No autonomic reflexes are possible in isolated preparations Arterial contraction due to the alpha agonist (choice E) is reversed by the alpha-blocker (choice C). Arteriolar relaxation and tachycardia due to epinephrine (choice B) is reversed by the beta-blocker (choice D). Bethanechol (choice A) causes both arteriolar relaxation and bradycardia.

Congestive heart failure can be precipitated by beta blockers. Choices (A), (C), and (E) reverse the correct pairing of receptor subtype (alpha versus beta) with effect. Choice (D) reverses the direction of change of intraocular pressure. The answer is (B). 

Until recently, the cardiotonics and a diuretic were the treatment of choice for HE However, other dragp such as the angiotensin-converting enzyme (ACE) inhibitors, and beta blockers have become the treatment of choice during the last several years. See Figure 39-1 for an example of a method of determining treatment for left ventricular systolic dysfunction. See Chapters 23, 42, and 46 for more information on the beta blockers, ACE inhibitors, and diuretics, respectively. 

Individual beta blockers are presented in Chapter 20. Beta blockers shown to be effective in treating arrhythmias include acebutolol, atenolol, esmolol, metoprolol, nadolol, propranolol, sotalol, and timolol (see Table 23-2). Choice of a specific beta blocker depends to a large extent on the exact type of arrhythmia present and the individual patient s response to the drug. 

Unstable angina although the therapy of choice for unstable angina rests on the use of beta-blockers and aspirin, calcium antagonists may add further value due to their spasmolytic effects. 

Beta-blockers - drug choice atenolol, bisoprolol or metoprolol... 

Q4 Beta-adrenoceptor (/3-adrenoreceptors) antagonists were originally introduced as anti-anginal agents. It was then noted that patients BP decreased over a period of weeks these agents have now been used to treat hypertension for many years. The beta-blockers (jS-blockers) are the agents of choice for young hypertensive patients. Their mechanism of action is unclear, but there are several components ... 

Q4 For young people with essential hypertension, either a beta-blocker fi-blocker) or an ACE inhibitor is recommended. For older patients, the medication of choice for hypertension is either a diuretic or calcium channel blocker. 

The drug of choice in young hypertensive patients is either a /3-blocker or an ACE inhibitor. Beta-blockers have several side effects, including... 

In 27 hypertensive patients aged 65 years or more, randomized to continue atenolol treatment for 20 weeks or to discontinue atenolol and start cilazapril, there was a significant improvement in the choice reaction time in the patients randomized to cilazapril (93). This study has confirmed previous reports that chronic beta-blockade can determine adverse effects on cognition in elderly patients. Withdrawal of beta-blockers should be... 

It produced a small reduction in hospitalizations due to heart failure (nine per 1000 patients-years) balanced by a significant increase in deaths from presumed dysrhythmias. Digitalis is therefore indicated for a small number of patients who have severe heart failure associated with sinus rhythm after treatment with diuretics, vasodilators, beta-blockers, and spironolactone. It remains the drug of first choice in patients with heart failure accompanied by fast atrial fibrillation, especially if due to myocardial or mitral valve disease. A trial of withdrawal of digitalis therapy can be considered in some cases (as noted in point 3 above). 

The effects of antihypertensive agents have been evaluated in patients taking ciclosporin. Collectively, dihydropyridine calcium channel blockers that do not affect ciclosporin blood concentrations substantially or at all (felodipine, isradipine, and nifedipine) are usually considered to be the drugs of choice. However, the risk of gingival hyperplasia with nifedipine, which ciclosporin also causes, should be borne in mind. Combination therapy with angiotensin-converting enzyme inhibitors or beta-blockers, or the use of other calcium channel blockers (verapamil or diltiazem) should also be considered, but careful monitoring of ciclosporin blood concentrations is recommended with the latter because they inhibit ciclosporin metabolism. 

Procedure Beta-lactam desensitization should be done in an intensive care unit and any concomitant risk factors for anaphylaxis, such as use of beta-blockers should be corrected. Protocols based on incremental use of the drug orally or parenterally have been described (190,193). The oral route is preferable and is associated with a lower incidence of adverse events, but mild transient reactions are frequent (171,194,195). Pregnant women with limited antibiotic choices have been treated with immunotherapy (196). Repeated administration will maintain a state of anergy, which is often lost after withdrawal (197). At the conclusion of therapy, patients must be informed that after withdrawal, they may once again become allergic to penicillin, with a new reaction to the first subsequent application (197). 

The effects of topical brimonidine and timolol have been compared in two trials in 926 subjects with glaucoma or ocular hypertension already using systemic beta-blockers (5). Concurrent systemic beta-blocker therapy had no deleterious effects on ocular hypotensive efficacy and no impact on safety with topical brimonidine, but the combination of timolol and brimonidine significantly reduced systolic and diastolic blood pressures and heart rate compared with brimonidine alone. This observation suggests that ocular hjrpotensive agents other than beta-blockers, such as brimonidine, may be appropriate as a first-choice therapy for glaucoma in patients concurrently taking systemic beta-blockers. 

Case Conclusion Diuretics and beta-blockers are first-line agents for treating HTN. Because this patient has asthma, beta-blockers should be avoided. Calcium channel blockers are favorable therapeutic options in patients with both angina and HTN. Because her heart rate is low, diltiazem and verapamil are not optimal choices because they can slow down AV nodal conduction. A long-acting dihydrof ridine, amlodipine, was started. 

B Because this patient has asthma and is wheezing, calcium channel blockers are the drug class of choice. Unlike beta-blockers and adenosine, they do not cause bronchospasm. Beta-blockers and adenosine should be used cautiously in patients with obstructive lung disease, and use should be avoided in patients with asthma. Digoxin is not contraindicated, but it is not the drug of choice due to its slow onset. Amiodarone is indicated for ventricular arrhythmias, but not PSVT. 

C The patient has COPD and renal impairment thus, the beta-blocker selected should be p, selective and hepatically cleared. Atenolol is renally cleared. Nadolol is nonselective and renally excreted. Both propranolol and labetolol are nonselective. Meto-prolol is the best choice because it is p, selective and hepatically eliminated. 

E Due to her concomitant disease states, AK should avoid beta-blockers, adrenergic agents, and sulfa medications. Pilocarpine is not a good choice for AK due to its bothersome local side effects. Latanoprost is a good initial choice for AK due to its convenient once daily dosing and mild local and systemic side effects. 

Figure II-4-5 The effects of Drug U are changed by treatment with the alpha-blocker, but not by the beta-blocker. Drug U must be an alpha-activator with no beta actions—the only choice is phenylephrine.

The pharmacology of diuretics is described later in a separate section. Both thiazide and loop diuretics are commonly used in the management of HTN. For the initial drug management of mild-to-moderate hypertension, the Joint National Committee (JNC) report VI recommends either a beta blocker or a thiazide diuretic as the drugs of first choice. 

Drugs of choice in bronchospasm caused by beta blockers. There are minor atropine-like... 

In symptomatic chronic heart failure, beta-blockers are also an essential component of an optimal medical regimen, as demonstrated in several trials (95-98). Currently extended-release metoprolol succinate, carve-dilol, and bisoprolol remain the agents of choice for treatment of patients with chronic ischemic heart disease and NYHA Class II-IV symptomatic heart failure. 

Much research has been conducted on the etiology of valvular dysfunction and the optimal timing for treatment. Pharmacologic treatment of valvular diseases with beta-blockers, ACE inhibitors, angiotensin receptor blockers and HMG-CoA reductase inhibitors can improve symptoms but has not been shown to effectively prolong survival. Thus, the treatment of choice for... 

Figure II-4-2 The effects of Drug R are changed by treatment with either an alpha or beta-blocker, so Drug R must have activity at both receptors (choices C, D, and E are ruled out). A pressor dose of epinephrine would be reversed by an alpha-blocker, not just decreased Drug R is norepinephrine.

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