Beta blockade

Calcium is contraindicated in patients with hypercalcemia or ventricular fibrillation and in patients taking digitalis. Calcium is used cautiously in patients with cardiac disease. Hypercalcemia may occur when calcium is administered with the thiazide diuretics. When calcium is administered with atenolol there is a decrease in Hie effect of atenolol, possibly resulting in decreased beta blockade. There is an increased risk of digitalis toxicity when digitalis preparations are administered with calcium. The clinical effect of verapamil may be decreased when the drug is administered with calcium. Concurrent ingestion of spinach or cereal may decrease file absorption of calcium supplements. 

II Beta blockade Slows atrioventricular conduction Propranolol, atenolol, esmolol... 

As propafenone exerts both beta blockade and a (dose-related) negative inotropic effect on cardiac muscle, fully compensate patients with CHF before receiving propafenone. If CHF worsens, discontinue propafenone unless CHF is due to the cardiac arrhythmia and, if indicated, restart at a lower dosage only after adequate cardiac compensation has been established. 

Detectable only at doses much greater than required for beta blockade. 

Muscle weakness Beta-blockade may potentiate muscle weakness consistent with certain myasthenic symptoms (eg, diplopia, ptosis, generalized weakness). Long-term therapy In long-term studies (2 and 3 years), no significant differences in mean lOP were observed after initial stabilization. 

Yusuf S, Peto R, Lewis J, et al. Beta blockade during and after myocardial infarction an overview of the randomized trials. Prog Cardiovasc Dis. Mar-Apr 1985 27(5) 335-371. 

Nagatsu M, Spinale FG, Koide M, et al. Bradycardia and the role of beta-blockade in the amelioration of left ventricular dysfunction. Circulation 2000 101 653-9. 

Andersson B, Lomsky M, Waagstein F. The link between acute haemodynamic adrenergic beta-blockade and long-term effects in patients with heart failure. A study on diastolic function, heart rate and myocardial metabolism following intravenous metoprolol. Eur. Heart J. 1993 14 1375-85. 

Groeiming BA, Nilsson JC, Hildebrandt PR, et al. Neurohumoral prediction of left-ventricular morphologic response to beta-blockade with metoprolol in chronic left-ventricular systolic heart failure. Eur. J. Heart Fail. 2002 4 635-46. 

Effect rednced by beta blockade Cardiac arrhythmia... 

XVb.3.2. Prophylaxis. There is little evidence to justify prophylactic endoscopic or surgical intervention in patients with varices which have not yet bled. Available trials have often been small and assumptions based upon aggregation may not be well justified. Non-selective beta-blockade with propanolol appears however to halve the risk of bleeding. 

Effective antihypertensive and probably antianginal agent (though not approved for this indication), especially for patients who develop symptomatic bradycardia with beta-blockade... 

Brantigan CO, Brantigan TA, Joseph N Effect of beta-blockade and beta-stimulation on stage fright. Am J Med 72 88-94, 1982... 

Siitonen L, Sonck T, Janne J Effect of beta-blockade on performance use of beta-blockade in bowling and in shooting competitions. J Int Med Res 5 395-366, 1977... 

Freemantle N et al Beta blockade after myocardial infarction Systematic review and meta regression analysis. BMJ 1999 318 1730. [PMID 10381708]... 

Maggio PM,Taheri PA Perioperative issues Myocardial ischemia and protection-beta-blockade. Surg Clin North Am 2005 85 1091. [PMID 16326195]... 

Beta-blockade (especially with nonselective agents such as propranolol) alters response to sympathomimetics with 13-agonist activity (eg, epinephrine). E> Blockers that undergo extensive first-pass metabolism may be affected by drugs capable of altering this process. 13 Blockers may reduce hepatic blood flow. 

Hart DW, Wolf SE, Chinkes DL, Lai SO, Ramzy PI, Herndon DN. Beta-blockade and growth hormone after burn. Ann Surg 2002 236(4) 450-6. 

Davidson NM, Corrall RJ, Shaw TR, French EB. Observations in man of hypoglycaemia during selective and non-selective beta-blockade. Scott Med J 1977 22(l) 69-72. 

Blohme G, Lager I, Lonnroth P, Smith U. Hypoglycemic symptoms in insulin-dependent diabetics. A prospective study of the influence of beta-blockade. Diabete Metab 1981 7(4) 235-8. 

Ambrosioni E, Bacchelli S, Esposti DD, Borghi C. Beta-blockade in hypertension and congestive heart failure. J Cardiovasc Pharmacol. 2001 38(suppl 3) S25-S31. 

Class III drugs currently in use include amiodarone, bretylium, dofetilide, and ibutilide (see Table 23-2). These drugs all exert their primary effects by prolonging repolarization in cardiac cells. Amiodarone, however, also appears to have some properties similar to drugs in other classes, and may help control arrhythmias by inhibiting sodium channel function (class I effect), by beta blockade (class II effect), or even by blocking calcium channels (class IV effect).5... 

Problem/lnfluence of Medication. Propranolol and the other beta blockers are successful in reducing various supraventricular arrhythmias. These drugs, however, also attenuate the cardiac response to exercise. Heart rate and cardiac output are lower at any absolute workload, and maximal heart rate and cardiac output are attenuated by beta blockade. Consequently, the exercise response of a patient taking a beta blocker will be less than if the patient is not tak-... 

Beta-blockade in brain, kidney, and peripheral adrenergic neurons has been proposed as contributing to the antihypertensive effect observed with 13-receptor blockers. In spite of conflicting evidence, the brain appears unlikely to be the primary site of the hypotensive action of these drugs, because some 6-blockers that do not readily cross the blood-brain barrier (eg, nadolol, described below) are nonetheless effective antihypertensive agents. 

Waagstein p Caidahl K, Wallentin I, Bergh CH, Hjalmarson A. Long-term beta-blockade in dilated cardiomyopathy. Effects of short- and long-term metoprolol treatment followed by withdrawal and readministration of metoprolol. Circulation 1989 80 551-563. 

CIBIS-Investigators-and-Committees. A randomized trial of beta-blockade in heart failure. The Cardiac Insufficiency Bisoprolol Study (CIBIS). Circulation 1994 90 1765-1773. 

Lee JT, Kroemer HK, Silberstein DJ, Funck-Brentano C, Lineberry MD, Wood AJ, Roden DM, Woosley RL. The role of genetically determined polymorphic drug metabolism in the beta-blockade produced by propafenone. N Engl J Med 1990 322 1764-1768. 

In acute MI, the ISIS-1 study [88] was organized to assess the effects of early beta-blockade with atenolol on cardiovascular mortality during the first week following infarction and after long-term (mean 20 months) follow-up. There was a 15% reduction in vascular deaths, especially in the early phase of MI. The difference in early mortality was mainly due to a reduction in electromechanical dissociation in the presence of atenolol. In this regard, atenolol is usually given by intravenous injection or infusion to treat cardiac arrhythmias, and it should be noted that atenolol induced atrial fibrillation in half of the so-predisposed patients [89]. 

Fig. 9.2 Correlation between biological half-life and added methylene units assessed by measuring 80% recovery from 50% beta-blockade of isoproterenol-induced tachycardia after iv administration to anesthetized dogs (n = 5) [12]. Error bars indicate 1 SD from the mean. Note that when n = 0, then 8 = 6.

The required pharmacological profile as ultimately obtained by esmolol is depicted in Fig. 9.3, which also clearly shows its difference from propranolol [12]. Upon intravenous infusion, esmolol quickly produces a pseudo-steady state of beta-blockade and when the infusion is stopped, the effects of esmolol rapidly disappear with a half-life of about 10 min. Alternatively, propranolol requires almost 2 h simply to reach a pseudo-steady state of beta-blockade, and then dissipates only very slowly with a half-life of almost 4 h. 

Akathisia has been reported in 16% of patients taking olanzapine (SEDA-21, 56). Three patients developed severe akathisia during treatment with olanzapine (20-25 mg/day) (87). In two, the akathisia resolved after withdrawal of olanzapine and in one of those olanzapine was well tolerated when reintroduced in combination with lorazepam. In the third patient, the akathisia was controlled by dosage reduction. A 33-year-old man with AIDS and a prior history of extrapyramidal symptoms with both typical antipsychotic drugs and risperidone developed dose-dependent akathisia with olanzapine 15-19 mg/day the akathisia responded to dosage reduction and beta-blockade (88). 

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... 

Glaister DH, Harrison MH, Allnutt MF. Environmental influences on cardiac activity. In Burley DM, Frier JH, Rondel RK, Taylor SH, editors. New Perspectives in Beta-blockade. Horsham, UK Ciba Laboratories, 1973 241. 

BETA-BLOCKERS COCAINE Risk of hypertensive crisis Cocaine produces both alpha- and beta-adrenergic agonist effects selective beta-blockade leads to unopposed alpha-agonism (vasoconstriction) Avoid concurrent use... 

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