Antiarrhythmic agent resident survival guide: Difference between revisions
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* | * Class IA agents are proarrhythmogenic and are associated with increased incidences of [[Torsade de Pointes]], ventricular tachycardia or [[ventricular fibrillation]]. If arrhythmia are observed with one class 1A agent all other class 1A agents should be avoided. Due to risk of proarrhythmia all class 1A drugs should be initiated in hospital. If QTC > 500 msec the drug should be stopped. | ||
* [[Disopyramide]] side-effects include anticholinergic effects (30%) including dry mouth, blurred vision, constipation, and urinary retention. Pyridostigmine (90 mg twelve hourly to 180 mg every eight hours) prevents or diminishes the anticholinergic effect of disopyramide and allows high tolerated doses of the drug. | * [[Disopyramide]] side-effects include anticholinergic effects (30%) including dry mouth, blurred vision, constipation, and urinary retention. Pyridostigmine (90 mg twelve hourly to 180 mg every eight hours) prevents or diminishes the anticholinergic effect of disopyramide and allows high tolerated doses of the drug. | ||
* Disopyramide-induced hypoglycemia has been noted. Other reported side effects includes nausea, vomiting, rash, cholestatic jaundice, and agranulocytosis. It prolongs repolarization and may cause proarrhythmia (VF, Torsade de Pointes) | * Disopyramide-induced hypoglycemia has been noted. Other reported side effects includes nausea, vomiting, rash, cholestatic jaundice, and agranulocytosis. It prolongs repolarization and may cause proarrhythmia (VF, Torsade de Pointes) | ||
Revision as of 19:45, 12 December 2013
Template:Antiarrhythmic agent Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Definition
Causes
Life Threatening Causes
Common Causes
Prognosis
Vaughan-Williams classification of antiarrhythmic agents
| Vaughan-Williams classification of antiarrhythmic agents | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Class IA | Class IB | Class IC | Class II | Class III | Class IV | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mechanism | Predominantly sodium channel blocker with some potassium channel blocking activity | Sodium channel blocking activity | *V1 receptor of GIT vasculatures *Antidiuretic effects | *Pure α1 agonist(Vasoconstrictive) *No β1 | *Predominant β1 agonist (↑contractility) *β2 arterial smooth muscle (Hypotensive) | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Agents | Quinidine, procainamide, disopyramide | Lidocaine, mexiletine, phenytoin | 2nd line septic shock | 1st line Neurogenic shock 3rd-4th line septic shock | *1st line cardiogenic shock * low output septic shock | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Effect | Slows conduction, & prolongs repolarization | Slow conduction in diseased tissues, shorten repolarization | 0.03 unit/min | 20-300 mcg/kg/min | 2.5-20 mcg/kg/min | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Indications | Pre-excited atrial arrhythmias PSVT, Ventricular tachycardia | Ventricular arrhythmia | *Coronary spasm *Splanchnic vasoconstriction | Reflex bradycardia (only α1) | Hypotension (β2) | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Complications | Quinidine - abdominal cramping, diarrhea, rash, cinchonism (hearing decrease, tinnitus, and blurred vision), thrombocytopenia, hemolytic anemia, lupus syndrome , granulomatous hepatitis, QRS widening and ventricular arrhythmias. | *Not in cardiogenic shock *Arrhythmia *Ischemia induced cardiotoxicity | *Ischemic heart *Gut ischemia | *Bradycardia *Heart block | *Hypotension (add α1 agonist) | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Do's
- Class IA agents are proarrhythmogenic and are associated with increased incidences of Torsade de Pointes, ventricular tachycardia or ventricular fibrillation. If arrhythmia are observed with one class 1A agent all other class 1A agents should be avoided. Due to risk of proarrhythmia all class 1A drugs should be initiated in hospital. If QTC > 500 msec the drug should be stopped.
- Disopyramide side-effects include anticholinergic effects (30%) including dry mouth, blurred vision, constipation, and urinary retention. Pyridostigmine (90 mg twelve hourly to 180 mg every eight hours) prevents or diminishes the anticholinergic effect of disopyramide and allows high tolerated doses of the drug.
- Disopyramide-induced hypoglycemia has been noted. Other reported side effects includes nausea, vomiting, rash, cholestatic jaundice, and agranulocytosis. It prolongs repolarization and may cause proarrhythmia (VF, Torsade de Pointes)
- Procainamide has side-effects similar to Quinidine.
Don'ts
- Do not start with low dose Dopamine dose to perfuse the kidney.