Arrhythmias drugs used

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. It is important for clinicians to understand AF, because it is associated with substantial morbidity and mortality and because many strategies for drug therapy are available. Drugs used to treat AF often have a narrow therapeutic index and a broad adverse effect profile. 

TABLE 6-6. Adverse Effects of Drugs Used to Treat Arrhythmias... 

Type Ic drugs profoundly slow conduction velocity while leaving refractoriness relatively unaltered. Although effective for both ventricular and supraventricular arrhythmias, their use for ventricular arrhythmias has been limited by the risk of proarrhythmia. 

Flecainide is a drug used for arrhythmias and is of particular use in ventricular arrhythmias and paroxysmal atrial fibrillation. Flecainide has a membrane-stabilising activity. Use of flecainide may precipitate serious arrhythmias, even in patients with no history of cardiovascular disease and with otherwise normal hearts. 

Amiodarone is a drug used for arrhythmias, which has very similar properties to flecainide. Both drugs may cause pneumonitis as a side-effect but risk is lower with flecainide. Signs of pneumonitis include progressive shortness of breath or cough. 

Drugs used for treating arrhythmia can have an effect on the electrical conduction system of the heart, its excitability, automatism, the size of the effective refractory period, and adrenergic and cholinergic heart innervation. Accordingly, compounds of various chemical classes can restore heart rate disturbances. 

The applicability of these results to other populations (eg, those without recent Mis) is uncertain. Considering the known proarrhythmic properties of procainamide and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, the use of procainamide and other antiarrhythmic agents should be reserved for patients with life-threatening ventricular arrhythmias. 

This is a class IB drug used primarily for the emergency treatment of ventricular arrhythmias. It has little effect on sinus node automaticity but depresses normal and abnormal forms of automaticity in Purkinje fibres. It is generally ineffective against supraventricular and accessory pathway-induced (e.g. WPW syndrome) arrhythmias. Lidocaine is relatively safe and free from adverse cardiovascular side effects. It causes minimal cardiodepression, although high doses can cause heart block. The most common side effect is a dose-related CNS toxicity. It is given intravenously as a bolus of 1 mg-kg-1 followed by an infusion of 20-50 pg-kg-l-min-1. 

Chapter 12 Vasodilators the Treatment of Angina Pectoris Chapter 13 Drugs Used in Heart Failure Chapter 14 Agents Used in Cardiac Arrhythmias Chapter 15 Diuretic Agents... 

Certain agents used for the treatment of arrhythmias do not fit the conventional class 1-4 organization. These include digitalis (already discussed in Chapter 13 Drugs Used in Heart Failure), adenosine, magnesium, and potassium. 

The use of spironolactone as a diuretic is discussed in Chapter 15 Diuretic Agents. The drug has benefits in heart failure greater than those predicted from its diuretic effects alone (see Chapter 13 Drugs Used in Heart Failure). Adverse effects reported for spironolactone include hyperkalemia, cardiac arrhythmia, menstrual abnormalities, gynecomastia, sedation, headache, gastrointestinal disturbances, and skin rashes. 

Non-sedating antihistamines (e.g. loratidine, e.g. Clarityn cetirizine, e.g. Benadryl, Piriteze, Zirtek clemastine), which can cause dangerous arrhythmias with antifungal agents (itraconazole, ketoconazole), antibiotics (erythromycin, clarithromycin) and drugs used to counteract acidity... 

Some drugs used for arrhythmias exert their actions through the autonomic nervous system by mimicking or antagonising the effects of the sympathetic or... 

Lip GYH, Kamath S. Adverse reactions of drugs used to treat arrhythmia. Adverse Drug React Bull 2000 201 767-70. 

Heel RC, Brogden RN, Speight TM, Avery GS. Disopyramide a review of its pharmacological properties and therapeutic use in treating cardiac arrhythmias. Drugs 1978 15(5) 331-68. 

Bryson HM, Palmer KJ, Langtry HD, Fitton A. Propafenone. A reappraisal of its pharmacology, pharmacokinetics and therapeutic use in cardiac arrhythmias. Drugs 1993 45(1) 85-130. 

---