Beta blockers Anaesthetics, local

VerUcchi et al. [36] found that antibiotics, analgesics/anti-inflammatories and steroid compounds are the therapeutic classes most abundantly administered in Italian hospitals, but consistent consumption of cardiovascular compounds, tranquilizers, anti-neoplastics and anaesthetics was also detected. According to other authors in other localities [32, 41], PhCs detected in the largest amounts in hospital effluents are antibiotics, anti-epUeptics, beta-blockers, Upid regulators and... 

Remember that T BP can occur when epinephrine-containing local anaesthetics are used with patients on beta-blockers - Sympathomimetics, below ... 

LIDOCAINE BETA-BLOCKERS 1. Risk of bradycardia (occasionally severe), l BP and heart failure with intravenous lidocaine 2. Risk of lidocaine toxicity due to T plasma concentrations of lidocaine, particularly with propranolol and nadolol 3. t plasma concentrations of propranolol and possibly some other beta-blockers 1. Additive negative inotropic and chronotropic effects 2. Uncertain, but possibly a combination of beta-blocker-induced 1 hepatic blood flow (due to 1 cardiac output) and inhibition of metabolism of lidocaine 3. Attributed to inhibition of metabolism by lidocaine 1. Monitor PR, BP and ECG closely watch for development of heart failure when intravenous lidocaine is administered to patients on beta-blockers 2. Watch for lidocaine toxicity 3. Be aware. Regional anaesthetics should be used cautiously in patients with bradycardia. Beta-blockers could cause dangerous hypertension due to stimulation of alpha-receptors if adrenaline is used with local anaesthetic... 

Propranolol reduces the clearance of bupivacaine and so theoretically the toxicity of bupivacaine may be increased. There has been a single report of enhanced bupivacaine cardiotoxicity in a patient also receiving metoproioi and digoxin. The coronary vasoconstriction caused by cocaine is increased by propranolol. Beta blockers may interact with adrenaline (epinephrine)-containing local anaesthetics. 

This section is mainly concerned with the class I antiarrhythmics, which also possess some local anaesthetic properties, and with class IH antiarrhythmics. Antiarrhythmics that fall into other classes are dealt with under beta blockers , (p.833), digitalis glycosides , (p.903), and calcium-channel blockers , (p.860). Some antiarrhythmics that do not fit into the Vaughan Williams classification (see Table 9.1 , (below)) are also included in this section (e.g. adenosine). Interactions in which the an-tiarrhythmic drug is the affecting substance, rather than the drug whose activity is altered, are dealt with elsewhere. 

Note that local anaesthetic preparations of lidocaine often contain adrenaline (epinephrine), which may interact with beta blockers, see Beta blockers -I- Inotropes and Vasopressors , p.848. 

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