Antidysrhythmic drugs,

Can be considered oral lidocaine antidysrhythmic drugs have not been shown to improve survival in patients with ventricular dysrhythmias class I antidysrhythmic drugs (e.g., tocainide) have increased the risk of death when used in patients with nondife-threatening dysrhythmias... 

Walker DK, Alabaster CT, Congrave GS, et al. Significance of metabolism in the disposition and action of the antidysrhythmic drug, dofetilide. In vitro studies and correlation with in vivo data. Drug Metab Dispos 1996 24 447-455. 

The anticholinergic effects of cannabis (127) may result in interactions with other drugs with anticholinergic effects, such as some antidysrhythmic drugs. 

Cardiovascular effects due to enhanced sympathetic activity include tachycardia, increased cardiac output, vasoconstriction, and increased arterial pressure. Myocardial infarction is the most common adverse cardiac effect (43), and there is an increased risk of myocardial depression when amide-type local anesthetics, such as bupivacaine, levobupivacaine, lidocaine, or ropivacaine are administered with antidysrhythmic drugs. 

Several reviews of the clinical pharmacology, actions, therapeutic uses, and adverse reactions and interactions of adenosine and ATP have appeared (1-4). After intravenous administration adenosine enters cells, disappearing from the blood with a half-life of less than 10 seconds intracellularly it is phosphorylated to cyclic AMP. Its mechanism of action as an antidysrhythmic drug is not known, but it may act by an effect at adenosine receptors on the cell membrane. Its electrophysiological effects are to prolong AV nodal conduction time by prolonging the AH interval, without an effect on the HV interval. The pharmacological and adverse effects of adenosine triphosphate are similar to those of adenosine. 

It is unwise to give antidysrhythmic drugs to patients with Brugada syndrome. 

In the Spanish Study of Sudden Death (SSD) amiodarone reduced all-cause mortality from 15.4 to 3.5% compared with metoprolol however, the mortality in those receiving no antidysrhythmic drugs at all was only 7.7%, and in those the effect of amiodarone was not significant (39). 

The incidence of cardiac dysrhythmias with amiodarone is under 3% (42), lower than with many other antidysrhythmic drugs, and several randomized controlled trials have failed to show any prodysrhythmic effect (43). 

In a nested case-control analysis of 5522 patients with a first prescription for an antidysrhythmic drug and no previous use of thyroid drugs, cases were defined as all patients who had started a thyroid-mimetic or antithyroid drug no sooner than 3 months after the start of an antidysrhythmic drug and controls were patients with a... 

The safety of antidysrhythmic drugs in children has not been thoroughly studied. However, the risk of prolongation of the QT interval seems to be considerably less than that in adults (226), although it has been reported with quinidine, disopyramide, amiodarone, sotalol, and diphemanil. 

Antidysrhythmic drugs with Class I activity reduce the rate of the fast inward sodium current during Phase I of the action potential and increase the duration of the effective refractory period expressed as a proportion of the total action potential duration. The action potential duration is itself affected in different ways by subgroups of the Class I drugs ... 

Antidysrhythmic drugs with class IV activity prolong total action potential duration by prolonging the plateau phase (phase III) of the action potential via calcium channel blockade. 

Other classifications of antidysrhythmic drugs have been proposed, but the most useful clinical classification... 

There have been many reviews of the pharmacology, clinical pharmacology, pharmacokinetics, and adverse effects and interactions of antidysrhythmic drugs (2-13). 

The patterns of adverse effects of the antidysrhythmic drugs depend on three features ... 

All antidysrhythmic drugs have effects on the cardiac conducting tissues and can all therefore cause cardiac dysrhythmias. 

Each antidysrhythmic drug has its own non-cardiac effects, which can result in adverse effects. These are summarized in Table 3. 

---