Propafenone

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Symptoms of overdose may include:

• tiredness
• slow or irregular heartbeat
• seizures

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Propafenone is the generic form of the brand-name drug Rythmol, which is used to treat atrial fibrillation and other types of arrhythmia.

This prescription medicine belongs to a class of drugs called anti-arrhythmics. It works by slowing nerve impulses in the heart to keep the heart's rhythm normal.

The U.S. Food and Drug Administration (FDA) approved propafenone in 1989. It's marketed as Rythmol by GlaxoSmithKline.

Propafenone Warnings

Propafenone contains a black box warning because it could cause a dangerous irregular heartbeat and increase the risk of death in certain people.

Tell your doctor if you have heart disease, or have had a heart attack, before taking this medicine.

Propafenone should only be used to treat a life-threatening irregular heartbeat.

Before starting on propafenone, tell your doctor about all of your past and present medical conditions, especially:

• Low blood pressure
• Heart failure
• A slow heartbeat
• Brugada syndrome (a heart condition)
• Asthma, emphysema, and other breathing disorders
• High or low levels of sodium, potassium, chloride, or bicarbonate in your blood
• Myasthenia gravis (a condition that causes muscle weakness)
• Liver or kidney disease
• Lupus (an autoimmune disease characterized by inflammation and other symptoms)

Propafenone can affect how artificial pacemakers work. If you have a pacemaker, your doctor will need to monitor your device carefully during your treatment.

This medicine can make it harder for your body to fight an infection. Try to avoid being around people who are sick.

Tell your doctor if you notice any signs of infection, which may include:

• Fever
• Sore throat
• Chills
• Skin rash

You can become dehydrated more easily while taking this medicine. Tell your doctor if you experience any of the following symptoms:

• Excessive diarrhea, sweating, or vomiting
• Extreme loss of appetite
• Decreased thirst

Tell your healthcare provider that you're taking propafenone before having any type of surgery, including a dental procedure.

This medicine may decrease sperm count in men and affect fertility. Talk to your doctor if this is a concern.

Keep all appointments with your doctor and laboratory while taking propafenone. You'll need to undergo frequent tests to monitor how your body responds to the drug.

Propafenone should be used with extreme caution in children. Safety and effectiveness haven't been confirmed in children.

Pregnancy and Propafenone

It's not known whether propafenone could harm an unborn baby. Tell your doctor if you're pregnant or might become pregnant while using this medicine.

You'll need to discuss the risks and benefits of taking this drug during pregnancy.

Propafenone passes into breast milk. Don't breastfeed a baby while using this medicine.

RYTHMOL is indicated to:

• prolong the time to recurrence of paroxysmal atrial fibrillation/flutter (PAF) associated with disabling symptoms in patients without structural heart disease.
• prolong the time to recurrence of paroxysmal supraventricular tachycardia (PSVT) associated with disabling symptoms in patients without structural heart disease.
• treat documented ventricular arrhythmias, such as sustained ventricular tachycardia that, in the judgment of the physician, are life-threatening. Initiate treatment in the hospital.

Usage Considerations:

• The use of RYTHMOL in patients with permanent atrial fibrillation (AF) or in patients exclusively with atrial flutter or PSVT has not been evaluated. Do not use RYTHMOL to control ventricular rate during AF.
• Some patients with atrial flutter treated with propafenone have developed 1:1 conduction, producing an increase in ventricular rate. Concomitant treatment with drugs that increase the functional atrioventricular (AV) nodal refractory period is recommended.
• The use of RYTHMOL in patients with chronic atrial fibrillation has not been evaluated.
• Because of the proarrhythmic effects of RYTHMOL, its use with lesser ventricular arrhythmias is not recommended, even if patients are symptomatic, and any use of the drug should be reserved for patients in whom, in the opinion of the physician, the potential benefits outweigh the risks.
• The effect of propafenone on mortality has not been determined [see BOXED WARNING].

CYP2D6 is a protein in your body that is involved in the elimination of propafenone and other drugs from your body. Some patients have less of this protein in their bodies, affecting how much of the drug gets eliminated. Levels of CYP2D6 can vary greatly between individuals, and those having less of this protein are known as "poor metabolizers." 

CYP2D6 testing is done to determine whether you are a poor metabolizer. If you are a poor metabolizer, the levels of propafenone in your blood can become too high. As a result you may be at an increased risk of having more side effects from propafenone. 

Your doctor may adjust your dose of propafenone if you are a poor metabolizer.

You should not use propafenone if you are allergic to it, or if you have:

• heart failure, or if you have recently had a heart attack;

• a genetic heart condition, especially a certain heart rhythm disorder called Brugada syndrome;

• a serious heart condition such as "sick sinus syndrome" or "AV block" (unless you have a pacemaker);

• severe low blood pressure, or history of slow heart beats that have caused you to faint;

• a severe or uncontrolled electrolyte imbalance (such as low levels of potassium in your blood); or

• a breathing disorder such as severe COPD (chronic obstructive pulmonary disease).

To make sure propafenone is safe for you, tell your doctor if you have:

• heart disease or prior heart attack;

• a breathing disorder;

• liver or kidney disease;

• lupus;

• myasthenia gravis; or

• if you have ever had an abnormal blood test called Antinuclear Antibody Test or ANA.

It is not known whether propafenone will harm an unborn baby. Tell your doctor if you are pregnant.

This medicine may affect fertility (ability to have children) in men. Talk with your doctor if you have concerns about this risk.

Propafenone can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.

Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not take this medicine in larger or smaller amounts or for longer than recommended.

You may take propafenone with or without food.

Your heart function may need to be checked with an electrocardiograph or ECG (sometimes called an EKG), before and during treatment with propafenone.

You may have very low blood pressure while taking this medication. Call your doctor if you are sick with vomiting or diarrhea, extreme thirst, loss of appetite, or if you are sweating more than usual.

While using propafenone, you may need frequent blood tests.

Store at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.

Grapefruit and grapefruit juice may interact with propafenone and lead to unwanted side effects. Avoid the use of grapefruit products while taking propafenone.

Usual Adult Dose for Atrial Fibrillation:

Initial dose:
Immediate release: 150 mg orally every 8 hours.
Extended release: 225 mg every 12 hours.

Maintenance dose:
Immediate release: May be increased at a minimum of 3 to 4 day intervals to 225 mg every 8 hours and, if necessary, to 300 mg every 8 hours.
Extended release: May be increased after 5 days of therapy to 325 mg every 12 hours. Doses up to 425 mg every 12 hours are necessary for some patients.

Usual Adult Dose for Atrial Flutter:

Initial dose:
Immediate release: 150 mg orally every 8 hours.
Extended release: 225 mg every 12 hours.

Maintenance dose:
Immediate release: May be increased at a minimum of 3 to 4 day intervals to 225 mg every 8 hours and, if necessary, to 300 mg every 8 hours.
Extended release: May be increased after 5 days of therapy to 325 mg every 12 hours. Doses up to 425 mg every 12 hours are necessary for some patients.

Usual Adult Dose for Ventricular Tachycardia:

Initial dose:
Immediate release: 150 mg orally every 8 hours.
Extended release: 225 mg every 12 hours.

Maintenance dose:
Immediate release: May be increased at a minimum of 3 to 4 day intervals to 225 mg every 8 hours and, if necessary, to 300 mg every 8 hours.
Extended release: May be increased after 5 days of therapy to 325 mg every 12 hours. Doses up to 425 mg every 12 hours are necessary for some patients.

Usual Adult Dose for Wolff-Parkinson-White Syndrome:

Initial dose:
Immediate release: 150 mg orally every 8 hours.
Extended release: 225 mg every 12 hours.

Maintenance dose:
Immediate release: May be increased at a minimum of 3 to 4 day intervals to 225 mg every 8 hours and, if necessary, to 300 mg every 8 hours.
Extended release: May be increased after 5 days of therapy to 325 mg every 12 hours. Doses up to 425 mg every 12 hours are necessary for some patients.

(pro PAF en one)

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Capsule Extended Release 12 Hour, Oral, as hydrochloride:

Rythmol SR: 225 mg, 325 mg, 425 mg [contains soybean lecithin]

Generic: 225 mg, 325 mg, 425 mg

Tablet, Oral, as hydrochloride:

Rythmol: 150 mg [DSC], 225 mg [DSC] [scored]

Generic: 150 mg, 225 mg, 300 mg

Cl is reduced and elimination half-life is increased.

Note: Patients who exhibit significant widening of QRS complex or second- or third-degree AV block may need dose reduction.

Atrial fibrillation (to prevent recurrence): Oral:

Extended release capsule: Initial: 225 mg every 12 hours; dosage increase may be made at a minimum of 5-day intervals; may increase to 325 mg every 12 hours; if further increase is necessary, may increase to 425 mg every 12 hours

Immediate release tablet: Initial: 150 mg every 8 hours; dosage increase may be made at minimum of 3- to 4-day intervals, may increase to 225 mg every 8 hours; if further increase is necessary, may increase to 300 mg every 8 hours

Paroxysmal supraventricular tachycardia (to prevent recurrence), ventricular arrhythmias:

Oral: Immediate release tablet: Initial: 150 mg every 8 hours; dosage increase may be made at minimum of 3- to 4-day intervals, may increase to 225 mg every 8 hours; if further increase is necessary, may increase to 300 mg every 8 hours

Alternate recommendations: Supraventricular tachycardia: Oral:

Immediate release: Initial: 150 mg every 8 hours; maximum maintenance dose: 300 mg every 8 hours (ACC/AHA/HRS [Page 2015]).

Extended release: Initial: 225 mg every 12 hours; maximum maintenance dose: 425 mg every 12 hours (ACC/AHA/HRS [Page 2015]).

Paroxysmal atrial fibrillation, pharmacologic cardioversion (off-label use): Oral: Note: May be used on an outpatient basis (“Pill-in-the-pocket”). An initial inpatient cardioversion trial should have been successful before sending patient home on this approach. Patient must be taking an AV nodal-blocking agent (eg, beta-blocker, nondihydropyridine calcium channel blocker) prior to initiation of antiarrhythmic.

Immediate release tablet: 450 mg (weight <70 kg), 600 mg (weight ≥70 kg). May not repeat in ≤24 hours (Alboni, 2004; AHA/ACC/HRS [January, 2014]).