Apart from beta-blockers, other anti-arrhythmics should only be initiated on specialist advice.
Prescribing Notes
- Shared care guidelines are available for:
- Amiodarone
- Dronedarone
- Mexiletine
- Anti-arrhythmics are complex agents; intravenous injections or infusions should be given according to specialist advice.
- Following any initiation on specialist advice, the patient should be referred to the relevant cardiology service to ensure appropriate management
- The management of a cardiac arrhythmia requires a precise diagnosis and electrocardiographic evidence is essential.
- Dronedarone is recommended for AF rhythm control in the setting of normal/mildly impaired stable LV function, HFpEF, ischaemic or valvular heart disease [ESC AF guideline]. It requires annual review with a specified cardiologist as per SCG and should be discontinued only if heart rate control is required (e.g. permanent AF) or the patient has heart failure.
- Amiodarone has a very long half-life and interacts with many drugs (see SCG). There is a potential for drug interactions to occur for several weeks (or even months) after treatment with it has been stopped.
- Propafenone is contraindicated in patients with significant structural heart disease or in patients with an incident of myocardial infarction within the last 3 months.
- Flecainide has a negative inotropic effect and can increase the electrical threshold in patients with pacemakers. It should be avoided after myocardial infarction.
- Sotalol is a non-selective beta-blocker with additional Class III anti-arrhythmic properties. Sotalol may cause polymorphic VT (torsades de pointes); it should be given with extreme caution with drugs known to prolong the QT interval, e.g. erythromycin, clarithromycin, chloroquine, haloperidol, lithium, tricyclic antidepressants, chlorpromazine. Sotalol should be used with caution in patients on diuretics and avoided in hypokalaemia. It is normally reserved for use in paroxysmal atrial fibrillation ‘For further information on drugs that can prolong the QT interval – see https://www.crediblemeds.org.
- The negative inotropic effects of anti-arrhythmic drugs tend to be additive. Therefore, special care is needed if two or more are used, especially in impaired myocardial function.
- Verapamil may be used in paroxysmal supraventricular tachycardia. It is also used to slow the ventricular rate in atrial fibrillation. However, it should be avoided in atrial fibrillation or flutter complicating Wolff-Parkinson-White syndrome where it may promote antero-grade conduction, which can potentially lead to ventricular fibrillation. It should be avoided in patients with impaired left ventricular function. There is a risk of potentially serious bradycardia if co-administered with beta-blockers or digoxin.