Metoprolol contraindications

The most serious side effects early in ACS are hypotension, bradycardia, and heart block. Initial acute administration of //-blockers is not appropriate for patients presenting with decompensated heart failure. However, therapy may be attempted in most patients before hospital discharge after treatment of acute heart failure. Diabetes mellitus is not a contraindication to //-blocker use. If possible intolerance to //-blockers is a concern (e.g., due to chronic obstructive pulmonary disease), a short-acting drug such as metoprolol or esmolol should be administered IV initially. 

There is some anecdotal evidence that atrioventricular nodal blockade with verapamil or a beta-blocker can also be effective. However, in two cases the addition of a beta-blocker (either atenolol or metoprolol) to treatment with class I antidysrhythmic drugs (cibenzoline in one case and flecainide in the other) did not prevent the occurrence of atrial flutter with a 1 1 response (47). However, the author suggested that in these cases, although the beta-blockers had not suppressed the dysrhythmia, they had at least improved the patient s tolerance of it. In both cases the uses of class I antidysrhythmic drugs was contraindicated by virtue of structural damage, in the first case due to mitral valvular disease and in the second due to an ischemic cardiomyopathy. 

C Diltiazem. Quinidine can be used to maintain normal sinus rhythm (NSR) after cardioversion of atrial fibrillation. Metoprolol is commonly used to control ventricular rate before conversion to NSR. However, this patient has two contraindications (COPD and diabetes) for beta-blocker use. Unlike diltiazem, amlodipine and nimodipine do not block AV nodal conduction therefore, they would be ineffective at rate control. 

Data regarding the acute benefit of /3-blockers in MI in the reperfusion era is derived mainly from the Thrombolysis in Myocardial Infarction (TIMI) II trial. In this trial, patients with ST-segment-elevation ACS were randomized to either IV metoprolol to be given as soon as possible following fibrinolytic administration followed by oral metoprolol or oral metoprolol deferred until day 6. Early administration of metoprolol was associated with a significant decrease in recurrent ischemia and early reinfarction. Patients receiving fibrinolytic therapy within 2 hours of symptom onset demonstrated the greatest benefit from early metoprolol administration. Based on the results of these trials, early administration of /8-blockers (to patients without contraindications) within the first 24 hours of hospital admission is a standard of quality patient care (see Table 16-3). 

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