Par Pharmaceutical Companies, Inc. announced that it began shipping the 225mg, 325mg, and 425mg strengths of propafenone SR capsules, the generic version of GlaxoSmithKline's Rythmol SR. Par has been awarded 180 days of marketing exclusivity, commencing at launch, for being the first to file an ANDA containing a paragraph IV certification for the product. According to IMS Health data, annual sales in the US of Rythmol are approximately $121 million.

Propafenone extended release capsules are indicated to prolong the time to recurrence of symptomatic atrial fibrillation in patients without structural heart disease.

The use of propafenone extended release capsules in patients with permanent atrial fibrillation or in patients exclusively with atrial flutter or PSVT has not been evaluated. Propafenone extended release capsules should not be used to control ventricular rate during atrial fibrillation.

The effect of propafenone extended release capsules on mortality has not been determined.

Propafenone extended release capsules are contraindicated in the presence of congestive heart failure, cardiogenic shock, sinoatrial, atrioventricular and intraventricular disorders of impulse generation or conduction (e.g., sick sinus node syndrome, atrioventricular block) in the absence of an artificial pacemaker, bradycardia, marked hypotension, bronchospastic disorders, electrolyte imbalance, or hypersensitivity to the drug.

Par Pharmaceutical Companies, Inc. is a US-based specialty pharmaceutical company. Through its wholly-owned subsidiary's two operating divisions, Par Pharmaceutical and Strativa Pharmaceuticals, it develops, manufactures and markets higher-barrier-to-entry generic drugs and niche, innovative proprietary pharmaceuticals.