The symptoms of overdosage may include hypotension, somnolence, bradycardia, intra-atrial and intra-ventricular conduction disturbances, and rarely convulsions and high grade ventricular arrhythmias. Defibrillation as well as infusion of dopamine and isoproterenol have been effective in controlling abnormal rhythm and blood pressure. Convulsions have been alleviated with intravenous diazepam. General supportive measures such as mechanical respiratory assistance and external cardiac massage may be necessary.

The hemodialysis of propafenone in patients with an overdose is expected to be of limited value in the removal of propafenone as a result of both its high protein binding ( > 95%) and large volume of distribution.

RYTHMOL SR is contraindicated in the following circumstances:

• Heart failure
• Cardiogenic shock
• Sinoatrial, atrioventricular and intraventricular disorders of impulse generation or conduction (e.g., sick sinus node syndrome, AV block) in the absence of an artificial pacemaker
• Bradycardia
• Marked hypotension
• Bronchospastic disorders or severe obstructive pulmonary disease
• Marked electrolyte imbalance

Last reviewed on RxList: 6/1/2011
This monograph has been modified to include the generic and brand name in many instances.