Propafenone is a drug used to prevent several irregular heart rhythms, most commonly paroxysmal atrial fibrillation. It is usually commenced by a Cardiologist and may be taken either on a regular basis or in a ‘pill-in-the-pocket’ fashion. 

Mechanism of action

Propafenone acts by preventing the passage of sodium into heart muscle cells thereby slowing electrical conduction.

Potential side-effects

Common side effects include an unusual taste (7-23%), dizziness (7-15%) and nausea (3-11%). Other more serious side effects include induction of other abnormal heart rhythms.  If you are started on Propafenone and experience any untoward effects it is essential that you seek medical advice.


Propafenone is a very useful drug but it should be used with caution usually prescribed only by a Cardiologist.  Its use should also be avoided in patients with a history of cardiac failure and liver failure.