Propafenone ER 225mg Capsules
WARNING: This drug is only to be used to treat certain types of abnormal heartbeats. Other abnormal heartbeats have happened with this drug. This can be deadly. Talk to the doctor if you have any questions about this drug. @ COMMON USES: It is used to treat certain types of abnormal heartbeats.
Drug Class
Antiarrhythmic
Pharmacologic Class
Class IC Antiarrhythmic (Sodium Channel Blocker)
Pregnancy Category
Category C
FDA Approved
Dec 2004
DEA Schedule
Not Controlled
Overview
What is this medicine?
Propafenone ER is a medication used to help keep your heart beating in a regular rhythm. It's often prescribed for conditions like atrial fibrillation, where the upper chambers of your heart beat too fast or irregularly. This extended-release capsule works by slowing down electrical signals in your heart to help maintain a normal rhythm.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided to you and follow the instructions closely. You can take this medication with or without food. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
When taking your medication, swallow the tablet whole. Do not chew, open, or crush it, as this can affect how the medication works.
Storing and Disposing of Your Medication
To keep your medication effective, store it at room temperature, away from light. Choose a dry location, such as a closet or drawer, and avoid storing it in the bathroom. Make sure to keep the lid tightly closed when not in use.
What to Do If You Miss a Dose
If you miss a dose, skip it and take your next dose at the usual time. Do not take two doses at the same time or take extra doses to make up for the missed one.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided to you and follow the instructions closely. You can take this medication with or without food. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
When taking your medication, swallow the tablet whole. Do not chew, open, or crush it, as this can affect how the medication works.
Storing and Disposing of Your Medication
To keep your medication effective, store it at room temperature, away from light. Choose a dry location, such as a closet or drawer, and avoid storing it in the bathroom. Make sure to keep the lid tightly closed when not in use.
What to Do If You Miss a Dose
If you miss a dose, skip it and take your next dose at the usual time. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take the capsule whole; do not crush, chew, or divide it.
- Take it consistently at the same time each day.
- Avoid grapefruit juice, as it can increase levels of the medication.
- Report any new or worsening heart palpitations, dizziness, shortness of breath, or chest pain immediately.
- Maintain regular follow-up appointments and blood tests as advised by your doctor.
- Inform all healthcare providers, including dentists, that you are taking propafenone.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 225 mg orally once daily. May be increased after 3-4 days to 325 mg once daily, then if needed, to 425 mg once daily.
Dose Range:
225 - 425 mg
Condition-Specific Dosing:
paroxysmal_atrial_fibrillation_flutter:
Initial: 225 mg once daily. Titrate based on efficacy and tolerability.
paroxysmal_supraventricular_tachycardia:
Initial: 225 mg once daily. Titrate based on efficacy and tolerability.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment recommended, but monitor closely.
Moderate:
No specific dose adjustment recommended, but monitor closely.
Severe:
Use with caution; monitor closely for adverse effects and consider lower doses.
Dialysis:
Not significantly dialyzable. Use with caution; monitor closely.
Hepatic Impairment:
Mild:
Reduce dose by 25-30% or extend dosing interval. Monitor closely.
Moderate:
Significant dose reduction (e.g., 50%) or extended dosing interval required. Monitor closely.
Severe:
Contraindicated due to extensive hepatic metabolism and risk of accumulation.
Confidence:
High
Pharmacology
Mechanism of Action
Propafenone is a Class IC antiarrhythmic agent. It exerts its effects by blocking fast sodium channels in myocardial cells, leading to a marked decrease in the maximum rate of depolarization (Vmax) of the action potential. This results in a significant slowing of conduction in the atria, AV node, and ventricles. It also possesses weak beta-blocking and calcium channel blocking properties, though its primary antiarrhythmic effect is due to sodium channel blockade.
Pharmacokinetics
Absorption:
Bioavailability:
Highly variable (5-50%) due to significant first-pass metabolism. Bioavailability increases disproportionately with increasing dose.
Tmax:
Approximately 3-4 hours (for ER formulation)
FoodEffect:
Food may increase Cmax and AUC slightly, but generally not clinically significant for ER formulation; can be taken with or without food.
Distribution:
Vd:
Approximately 1.9-3.0 L/kg
ProteinBinding:
Approximately 95% (primarily to alpha1-acid glycoprotein and albumin)
CnssPenetration:
Limited, but can cause CNS side effects at higher concentrations.
Elimination:
HalfLife:
Biphasic elimination. For extensive metabolizers: 2-10 hours (propafenone), 6-16 hours (5-hydroxypropafenone). For poor metabolizers: 10-32 hours (propafenone).
Clearance:
Highly variable due to genetic polymorphism.
ExcretionRoute:
Renal (approximately 38% as metabolites, <1% unchanged), Fecal (approximately 53% as metabolites).
Unchanged:
<1%
Pharmacodynamics
OnsetOfAction:
Within 1 hour (immediate release); for ER, steady-state effects are achieved after several days of dosing.
PeakEffect:
3-4 hours (for ER formulation, reflecting Tmax)
DurationOfAction:
24 hours (for ER formulation, allowing once-daily dosing)
Confidence:
High
Safety & Warnings
BLACK BOX WARNING
PROARHYTHMIC EFFECTS: Propafenone is a Class IC antiarrhythmic agent. Class IC antiarrhythmic drugs used to treat supraventricular arrhythmias, including propafenone, have caused proarrhythmic events (e.g., new or worsened arrhythmias) in patients with structural heart disease. Therefore, propafenone is contraindicated in patients with structural heart disease (e.g., myocardial infarction, heart failure, or left ventricular dysfunction).
Side Effects
Serious Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Chest pain or pressure
Fast or slow heartbeat
Severe dizziness or fainting
New or worsening abnormal heartbeat
Blurred vision
Heart-Related Side Effects
This medication may increase the risk of heart failure, including worsening of existing heart disease. If you have a history of heart disease, inform your doctor. Seek medical attention immediately if you experience:
Shortness of breath
Sudden weight gain
Abnormal heartbeat
New or worsening swelling in the arms or legs
Infection-Related Side Effects
Drugs like this one may lower white blood cell counts, increasing the risk of infection. Rarely, these infections can be fatal. If you have a history of low white blood cell count, inform your doctor. Seek medical attention immediately if you experience signs of infection, such as:
Fever
Chills
Sore throat
Other Side Effects
Most people taking this medication do not experience serious side effects. However, some may occur. If you experience any of the following side effects, contact your doctor or seek medical attention if they bother you or do not go away:
Dizziness, tiredness, or weakness
Upset stomach or vomiting
Constipation
Change in taste
Headache
Anxiety
Signs of a common cold
Reporting Side Effects
This is not an exhaustive list of potential side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Chest pain or pressure
Fast or slow heartbeat
Severe dizziness or fainting
New or worsening abnormal heartbeat
Blurred vision
Heart-Related Side Effects
This medication may increase the risk of heart failure, including worsening of existing heart disease. If you have a history of heart disease, inform your doctor. Seek medical attention immediately if you experience:
Shortness of breath
Sudden weight gain
Abnormal heartbeat
New or worsening swelling in the arms or legs
Infection-Related Side Effects
Drugs like this one may lower white blood cell counts, increasing the risk of infection. Rarely, these infections can be fatal. If you have a history of low white blood cell count, inform your doctor. Seek medical attention immediately if you experience signs of infection, such as:
Fever
Chills
Sore throat
Other Side Effects
Most people taking this medication do not experience serious side effects. However, some may occur. If you experience any of the following side effects, contact your doctor or seek medical attention if they bother you or do not go away:
Dizziness, tiredness, or weakness
Upset stomach or vomiting
Constipation
Change in taste
Headache
Anxiety
Signs of a common cold
Reporting Side Effects
This is not an exhaustive list of potential side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- New or worsening irregular heartbeats (palpitations)
- Severe dizziness or fainting (syncope)
- Shortness of breath or difficulty breathing
- Chest pain or discomfort
- Swelling in ankles or feet
- Unusual bruising or bleeding
- Yellowing of skin or eyes (jaundice)
- Dark urine or light-colored stools
- Persistent nausea, vomiting, or loss of appetite
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced.
Certain health conditions, including:
+ Breathing or lung problems
+ Brugada syndrome
+ Electrolyte imbalances in your blood
+ Low blood pressure
+ Recent heart attack
+ Sick sinus syndrome or heart block without a functioning pacemaker
+ Shock caused by heart problems
+ Slow heartbeat
+ Heart failure
If you have been taking medications to treat an abnormal heartbeat
Any medications you are currently taking, including prescription and over-the-counter drugs, natural products, and vitamins, as some may interact with this medication. Specifically, certain drugs used to treat HIV, infections, depression, and other conditions should not be taken with this medication. Your doctor or pharmacist can advise you on potential interactions.
Please note that this is not an exhaustive list of all possible interactions. To ensure your safety, it is crucial to:
Inform your doctor and pharmacist about all your medications and health conditions
Verify that it is safe to take this medication with your existing medications and health conditions
* Avoid starting, stopping, or changing the dose of any medication without consulting your doctor first.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced.
Certain health conditions, including:
+ Breathing or lung problems
+ Brugada syndrome
+ Electrolyte imbalances in your blood
+ Low blood pressure
+ Recent heart attack
+ Sick sinus syndrome or heart block without a functioning pacemaker
+ Shock caused by heart problems
+ Slow heartbeat
+ Heart failure
If you have been taking medications to treat an abnormal heartbeat
Any medications you are currently taking, including prescription and over-the-counter drugs, natural products, and vitamins, as some may interact with this medication. Specifically, certain drugs used to treat HIV, infections, depression, and other conditions should not be taken with this medication. Your doctor or pharmacist can advise you on potential interactions.
Please note that this is not an exhaustive list of all possible interactions. To ensure your safety, it is crucial to:
Inform your doctor and pharmacist about all your medications and health conditions
Verify that it is safe to take this medication with your existing medications and health conditions
* Avoid starting, stopping, or changing the dose of any medication without consulting your doctor first.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Your doctor will also require you to undergo regular blood tests, and it is crucial to discuss the results with them.
This medication may interfere with certain laboratory tests, so it is vital to notify all your healthcare providers and laboratory personnel that you are taking this drug. If you have previously had an abnormal Antinuclear Antibody Test (ANA test), you should discuss this with your doctor.
If you have myasthenia gravis, it is crucial to consult with your doctor, as this condition may worsen during treatment with this medication. Monitor your symptoms closely, and if they deteriorate, contact your doctor immediately. Additionally, if you have a defibrillator or pacemaker, you should discuss this with your doctor.
Before starting this medication and during treatment, you will need to undergo an electrocardiogram (ECG). Your doctor will schedule this test and discuss the results with you.
To avoid potential interactions, do not consume grapefruit or grapefruit juice while taking this medication. It is also essential to notify your doctor if you experience any signs of dehydration, such as excessive sweating, vomiting, diarrhea, decreased appetite, or unusual thirst.
This medication may decrease sperm counts, which could affect fertility. If you have concerns about this, discuss them with your doctor. Furthermore, if you are pregnant, plan to become pregnant, or are breastfeeding, you should consult with your doctor to weigh the benefits and risks of this medication for both you and your baby.
This medication may interfere with certain laboratory tests, so it is vital to notify all your healthcare providers and laboratory personnel that you are taking this drug. If you have previously had an abnormal Antinuclear Antibody Test (ANA test), you should discuss this with your doctor.
If you have myasthenia gravis, it is crucial to consult with your doctor, as this condition may worsen during treatment with this medication. Monitor your symptoms closely, and if they deteriorate, contact your doctor immediately. Additionally, if you have a defibrillator or pacemaker, you should discuss this with your doctor.
Before starting this medication and during treatment, you will need to undergo an electrocardiogram (ECG). Your doctor will schedule this test and discuss the results with you.
To avoid potential interactions, do not consume grapefruit or grapefruit juice while taking this medication. It is also essential to notify your doctor if you experience any signs of dehydration, such as excessive sweating, vomiting, diarrhea, decreased appetite, or unusual thirst.
This medication may decrease sperm counts, which could affect fertility. If you have concerns about this, discuss them with your doctor. Furthermore, if you are pregnant, plan to become pregnant, or are breastfeeding, you should consult with your doctor to weigh the benefits and risks of this medication for both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe hypotension (low blood pressure)
- Bradycardia (slow heart rate)
- Intraventricular conduction disturbances (e.g., QRS widening, AV block)
- Ventricular tachycardia or fibrillation
- Seizures
- Coma
- Respiratory depression
What to Do:
Immediately call 911 or your local emergency number. For advice, call a poison control center at 1-800-222-1222. Treatment is supportive and may include IV fluids, vasopressors, atropine, temporary pacing, and in severe cases, extracorporeal membrane oxygenation (ECMO) or lipid emulsion therapy.
Drug Interactions
Contraindicated Interactions
- Ritonavir (and other potent CYP3A4/2D6 inhibitors)
- Quinidine (in poor metabolizers of propafenone)
- Patients with structural heart disease (e.g., myocardial infarction, heart failure) due to proarrhythmic risk.
Major Interactions
- Digoxin (increases digoxin levels significantly)
- Warfarin (potentiates anticoagulant effect)
- Beta-blockers (e.g., metoprolol, propranolol - increased levels of both drugs)
- Calcium channel blockers (e.g., verapamil, diltiazem - increased levels of both drugs, additive cardiac depression)
- Other antiarrhythmics (e.g., amiodarone, flecainide - increased proarrhythmic risk, altered metabolism)
- Local anesthetics (e.g., lidocaine - increased CNS and cardiac toxicity)
- CYP2D6 inhibitors (e.g., fluoxetine, paroxetine, sertraline - significantly increase propafenone levels)
- CYP3A4 inhibitors (e.g., ketoconazole, erythromycin - increase propafenone levels)
Moderate Interactions
- Cimetidine (increases propafenone levels)
- Rifampin (decreases propafenone levels)
- Grapefruit juice (may increase propafenone levels)
- Theophylline (propafenone may increase theophylline levels)
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Electrocardiogram (ECG)
Rationale: To assess baseline cardiac rhythm, PR, QRS, and QT intervals, and identify pre-existing conduction abnormalities.
Timing: Before initiation of therapy.
Electrolytes (Potassium, Magnesium)
Rationale: To ensure normal levels, as imbalances can increase proarrhythmic risk.
Timing: Before initiation of therapy.
Renal function (BUN, Creatinine)
Rationale: To assess kidney function, as metabolites are renally excreted.
Timing: Before initiation of therapy.
Liver function tests (ALT, AST, Bilirubin)
Rationale: To assess hepatic function, as propafenone is extensively metabolized by the liver.
Timing: Before initiation of therapy.
Complete Blood Count (CBC)
Rationale: To establish baseline and monitor for potential hematologic abnormalities (rare).
Timing: Before initiation of therapy.
Routine Monitoring
Electrocardiogram (ECG)
Frequency: Regularly (e.g., weekly during titration, then every 3-6 months or as clinically indicated)
Target: QRS duration <25% increase from baseline; PR and QT intervals within normal limits or acceptable for patient.
Action Threshold: If QRS duration increases by >25% or if new conduction abnormalities (e.g., AV block, bundle branch block) or proarrhythmia occur, reduce dose or discontinue.
Blood Pressure and Heart Rate
Frequency: Regularly (e.g., at each visit)
Target: Within patient's normal range.
Action Threshold: Significant bradycardia or hypotension.
Electrolytes (Potassium, Magnesium)
Frequency: Periodically (e.g., every 3-6 months or as clinically indicated, especially if on diuretics)
Target: Potassium 3.5-5.0 mEq/L, Magnesium 1.8-2.4 mg/dL.
Action Threshold: Correct imbalances promptly.
Liver function tests (ALT, AST)
Frequency: Periodically (e.g., every 6-12 months or as clinically indicated)
Target: Within normal limits.
Action Threshold: Significant elevation (e.g., >3x ULN) may require dose reduction or discontinuation.
Symptom Monitoring
- Palpitations (new or worsening)
- Dizziness or lightheadedness
- Shortness of breath
- Chest pain
- Syncope or pre-syncope
- Fatigue
- Nausea, vomiting, constipation
- Unusual bleeding or bruising (if on warfarin)
- Signs of liver dysfunction (e.g., jaundice, dark urine, persistent nausea)
Special Patient Groups
Pregnancy
Propafenone is classified as Pregnancy Category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Animal studies have shown adverse effects on the fetus at doses higher than human therapeutic doses.
Trimester-Specific Risks:
First Trimester:
Potential for teratogenicity observed in animal studies at high doses. Human data are limited.
Second Trimester:
Limited human data. Monitor fetal heart rate and growth.
Third Trimester:
Limited human data. Potential for neonatal effects (e.g., bradycardia) if used close to term.
Lactation
Propafenone and its active metabolites are excreted into human breast milk. Due to the potential for serious adverse reactions in the nursing infant, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. The American Academy of Pediatrics considers it a drug for which the effect on nursing infants is unknown but may be of concern.
Infant Risk:
L3 (Moderate concern). Potential for bradycardia, conduction disturbances, or other adverse effects in the infant. Monitor infant for signs of adverse effects.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Use is generally not recommended.
Geriatric Use
Use with caution in elderly patients, as they may be more susceptible to adverse effects, particularly proarrhythmia and CNS effects. Start with lower doses and titrate slowly, monitoring closely for adverse reactions and drug interactions. Renal and hepatic function may be diminished, requiring dose adjustments.
Clinical Information
Clinical Pearls
- Propafenone ER is specifically designed for once-daily dosing, improving patient adherence compared to immediate-release formulations.
- Always rule out structural heart disease before initiating propafenone due to the significant proarrhythmic risk (Black Box Warning).
- Genetic polymorphism of CYP2D6 significantly impacts propafenone metabolism. Poor metabolizers will have higher and more prolonged drug levels, requiring lower doses.
- Monitor ECG closely, especially QRS duration. A QRS widening of >25% from baseline suggests excessive sodium channel blockade and warrants dose reduction or discontinuation.
- Correct electrolyte imbalances (especially hypokalemia and hypomagnesemia) before and during propafenone therapy to minimize proarrhythmic risk.
- Be vigilant for drug interactions, particularly with digoxin, warfarin, beta-blockers, calcium channel blockers, and strong CYP2D6/3A4 inhibitors.
- Patients should be advised to report any new or worsening symptoms, especially those related to cardiac rhythm or liver function.
Alternative Therapies
- Flecainide (another Class IC antiarrhythmic, similar contraindications)
- Amiodarone (Class III antiarrhythmic, broad spectrum, different side effect profile)
- Dofetilide (Class III antiarrhythmic, requires hospitalization for initiation)
- Sotalol (Class II/III antiarrhythmic)
- Catheter ablation (non-pharmacological intervention for AF/PSVT)
- Cardioversion (for acute rhythm control)
Cost & Coverage
Average Cost:
$100 - $300 per 30 capsules
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (generic), Tier 3 or Non-Formulary (brand)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.