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Importantly, patients should not take a beta-blocker if they have reactive airways disease, symptomatic bradycardia or advanced heart block (unless treated with a pacemaker).

Initiation and maintenance

Treatment with a beta-blocker should be initiated at very low doses, followed by gradual increments in dose if lower doses have been well tolerated.

Patients should be monitored closely for changes in vital signs and symptoms during this up-titration period. In addition, because initiation of therapy with a beta-blocker can cause fluid retention76, physicians should ask patients to weigh themselves daily and to manage any increase in weight by immediately increasing the dose of concomitantly administered diuretics until weight is restored to pretreatment levels.

Planned increments in the dose of a beta-blocker should be delayed until any side effects observed with lower doses have disappeared. Using such a cautious approach, most patients (approximately 85%) enrolled in clinical trials with beta-blockers were able to tolerate short- and long-term treatment with these drugs and achieve the maximum planned trial dose.

As with ACE inhibitors, the dose of beta-blockers in controlled clinical trials was not determined by a patient’s therapeutic response but was increased until the patient received a pre-specified target dose. Low doses were prescribed only if the target doses were not tolerated, and thus, most trials did not evaluate whether low doses would be effective. Therefore, physicians should make every effort to achieve the target doses of the beta-blockers shown to be effective in major clinical trials. Once the target dose has been achieved, patients can generally be maintained on long-term therapy with a beta- blocker with little difficulty.

Patients should be advised that clinical responses to the drug are generally delayed and may require 2 to 3 months to become apparent. Even if symptoms do not improve, long- term treatment should be maintained to reduce the risk of major clinical events.

Abrupt withdrawal of treatment with a beta-blocker can lead to clinical deterioration and should be avoided77. Even if patients develop fluid retention, with or without mild symptoms, it is reasonable to continue the beta-blocker while the dose of diuretic is increased. However, if the deterioration in clinical status is characterized by hypoperfusion or requires the use of intravenous positive inotropic drugs, it may be prudent to stop treatment with the beta-blocker temporarily until the status of the patient

76 Gaffney TE, Braunwald E. Importance of the adrenergic nervous system in the support of circulatory function in patients with congestive heart failure. Am J Med 2000;34:320-4.

77 Waagstein F, Caidahl K,Wallentin I, Bergh CH, Hjalmarson A. Longterm beta-blockade in dilated cardiomyopathy: effects of short- and long-term metoprolol treatment followed by withdrawal and readministration of metoprolol. Circulation 1989;80:551-63.

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