Propafenone 225mg Tablets
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
Pregnancy Category
Category C
FDA Approved
Oct 1989
DEA Schedule
Not Controlled
Overview
What is this medicine?
Propafenone is a medication used to treat certain types of irregular heartbeats (arrhythmias). It works by helping to stabilize the electrical activity in your heart, making it beat more regularly. It's often used for conditions like atrial fibrillation or other fast heart rhythms.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. It's essential to continue taking this medication as prescribed by your doctor or healthcare provider, even if you're feeling well.
Storing and Disposing of Your Medication
To maintain the quality and effectiveness of your medication, store it at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep the lid tightly closed when not in use.
Missing a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. It's essential to continue taking this medication as prescribed by your doctor or healthcare provider, even if you're feeling well.
Storing and Disposing of Your Medication
To maintain the quality and effectiveness of your medication, store it at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep the lid tightly closed when not in use.
Missing a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take exactly as prescribed, do not skip doses or take extra.
- Do not crush, chew, or break extended-release tablets (if applicable).
- Avoid grapefruit and grapefruit juice, as they can increase the amount of propafenone in your body.
- Report any new or worsening symptoms of irregular heartbeat, dizziness, fainting, chest pain, or shortness of breath immediately.
- Inform your doctor and dentist that you are taking propafenone before any procedures or surgeries.
- Carry a medical alert card or wear a medical alert bracelet indicating you are taking propafenone.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 150 mg every 8 hours. May increase to 225 mg every 8 hours after 3-4 days, then 300 mg every 8 hours if needed. Maintenance: 150-300 mg every 8 hours.
Dose Range:
450 - 900 mg
Condition-Specific Dosing:
paroxysmalSupraventricularTachycardia:
Initial: 150 mg every 8 hours. Max: 300 mg every 8 hours.
paroxysmalAtrialFibrillationFlutter:
Initial: 150 mg every 8 hours. Max: 300 mg every 8 hours.
ventricularArrhythmias:
Initial: 150 mg every 8 hours. Max: 300 mg every 8 hours.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established (limited data, generally not recommended due to proarrhythmia risk)
Adolescent:
Not established (limited data, generally not recommended due to proarrhythmia risk)
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment recommended, but monitor closely.
Moderate:
No specific adjustment recommended, but monitor closely.
Severe:
Use with caution; monitor ECG and plasma concentrations if possible.
Dialysis:
Not significantly dialyzable. Use with caution, monitor ECG and plasma concentrations.
Hepatic Impairment:
Mild:
Reduce dose by 20-30% or extend dosing interval.
Moderate:
Reduce dose by 50% or more; monitor ECG and plasma concentrations.
Severe:
Contraindicated or use with extreme caution at significantly reduced doses; monitor ECG and plasma concentrations.
Pharmacology
Mechanism of Action
Propafenone is a Class Ic antiarrhythmic agent. It acts by blocking fast voltage-gated sodium channels in myocardial cells, leading to a decrease in the maximum rate of depolarization (Vmax) of the action potential. This results in a marked reduction in impulse conduction velocity in the atria, AV node, and ventricles, and a prolongation of the effective refractory period in the atria and accessory pathways. It also possesses weak beta-blocking and calcium channel blocking activity.
Pharmacokinetics
Absorption:
Bioavailability:
3.4-10.6% (extensive metabolizers); 20-50% (poor metabolizers) due to significant first-pass metabolism
Tmax:
3-4 hours (immediate release)
FoodEffect:
Food may increase bioavailability slightly but is not clinically significant for administration.
Distribution:
Vd:
1.9-3.0 L/kg
ProteinBinding:
Approximately 95% (primarily to alpha1-acid glycoprotein and albumin)
CnssPenetration:
Limited
Elimination:
HalfLife:
2-10 hours (extensive metabolizers); 10-32 hours (poor metabolizers)
Clearance:
Not available (highly variable due to first-pass and polymorphism)
ExcretionRoute:
Urine (38-57%), Feces (18-38%)
Unchanged:
Approximately 1% (urine)
Pharmacodynamics
OnsetOfAction:
Within 1 hour
PeakEffect:
3-4 hours
DurationOfAction:
Approximately 8 hours (for immediate release)
Safety & Warnings
BLACK BOX WARNING
Propafenone is contraindicated in patients with structural heart disease (e.g., myocardial infarction, heart failure, or left ventricular dysfunction) because of an increased risk of proarrhythmia (new or worsened arrhythmia) and mortality. The use of propafenone in patients with structural heart disease is associated with a 2- to 2.5-fold increase in mortality compared to placebo. It should be reserved for patients with life-threatening ventricular arrhythmias or for patients with supraventricular arrhythmias who do not have structural heart disease and for whom other treatments are ineffective or not tolerated.
Side Effects
Urgent Side Effects: Seek Medical Attention Immediately
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical help right away:
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 passing out
Abnormal heartbeat that is new or worse
Blurred eyesight
Important Warnings
Heart failure has been associated with this medication, and it can worsen existing heart disease. If you have a history of heart disease, inform your doctor. Seek immediate medical attention if you experience:
Shortness of breath
Sudden weight gain
Abnormal heartbeat
Swelling in the arms or legs that is new or worsening
Additionally, this medication can cause low white blood cell counts, which may increase the risk of infection. If you have a history of low white blood cell counts, inform your doctor. Seek medical attention if you experience signs of infection, such as:
Fever
Chills
Sore throat
Other Possible Side Effects
Most people do not experience significant side effects, but some may occur. If you experience any of the following side effects, contact your doctor or seek medical help if they bother you or do not go away:
Dizziness
Fatigue
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 possible 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.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical help right away:
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 passing out
Abnormal heartbeat that is new or worse
Blurred eyesight
Important Warnings
Heart failure has been associated with this medication, and it can worsen existing heart disease. If you have a history of heart disease, inform your doctor. Seek immediate medical attention if you experience:
Shortness of breath
Sudden weight gain
Abnormal heartbeat
Swelling in the arms or legs that is new or worsening
Additionally, this medication can cause low white blood cell counts, which may increase the risk of infection. If you have a history of low white blood cell counts, inform your doctor. Seek medical attention if you experience signs of infection, such as:
Fever
Chills
Sore throat
Other Possible Side Effects
Most people do not experience significant side effects, but some may occur. If you experience any of the following side effects, contact your doctor or seek medical help if they bother you or do not go away:
Dizziness
Fatigue
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 possible 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 more frequent palpitations (feeling your heart race or skip beats)
- Severe dizziness or lightheadedness
- Fainting spells (syncope)
- Chest pain or discomfort
- Shortness of breath or difficulty breathing
- Swelling in your ankles, feet, or legs
- Unusual fatigue or weakness
- Yellowing of the skin or eyes (jaundice)
- Dark urine or pale stools
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. Describe the allergic reaction you experienced, including the symptoms that occurred.
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 any medications to treat abnormal heart rhythms
If you are taking any prescription or over-the-counter (OTC) medications, natural products, or vitamins that may interact with this medication. Certain medications, such as those used to treat HIV, infections, or depression, should not be taken with this drug. Your doctor or pharmacist can advise you on potential interactions.
Please note that this is not an exhaustive list of all possible interactions or health problems that may affect the use of this medication. To ensure your safety, it is crucial to:
Inform your doctor and pharmacist about all your medications (prescription and OTC), natural products, vitamins, and health conditions
Verify that it is safe to take this medication with all your other 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. Describe the allergic reaction you experienced, including the symptoms that occurred.
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 any medications to treat abnormal heart rhythms
If you are taking any prescription or over-the-counter (OTC) medications, natural products, or vitamins that may interact with this medication. Certain medications, such as those used to treat HIV, infections, or depression, should not be taken with this drug. Your doctor or pharmacist can advise you on potential interactions.
Please note that this is not an exhaustive list of all possible interactions or health problems that may affect the use of this medication. To ensure your safety, it is crucial to:
Inform your doctor and pharmacist about all your medications (prescription and OTC), natural products, vitamins, and health conditions
Verify that it is safe to take this medication with all your other 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. Regular blood tests will be necessary, as directed by your doctor, to monitor your condition. Be sure to discuss any concerns or questions you have with your doctor.
This medication may interfere with certain laboratory tests, so it is crucial to notify all your healthcare providers and laboratory personnel that you are taking this drug.
If you have previously had an abnormal result on an Antinuclear Antibody Test (ANA test), consult with your doctor before starting treatment. Additionally, if you have myasthenia gravis, discuss your condition with your doctor, as this medication may worsen symptoms. If you experience any worsening of symptoms, contact your doctor promptly.
If you have a defibrillator or pacemaker, consult with your doctor before starting treatment. An electrocardiogram (ECG) will be required before initiating this medication and periodically during treatment. Discuss the details with your doctor.
To avoid potential interactions, do not consume grapefruit or grapefruit juice while taking this medication.
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 count, which could affect fertility. If you have concerns about fathering a child, discuss this with your doctor.
If you are pregnant, planning to become pregnant, or breastfeeding, consult with your doctor to weigh the benefits and risks of this medication to both you and your baby.
This medication may interfere with certain laboratory tests, so it is crucial to notify all your healthcare providers and laboratory personnel that you are taking this drug.
If you have previously had an abnormal result on an Antinuclear Antibody Test (ANA test), consult with your doctor before starting treatment. Additionally, if you have myasthenia gravis, discuss your condition with your doctor, as this medication may worsen symptoms. If you experience any worsening of symptoms, contact your doctor promptly.
If you have a defibrillator or pacemaker, consult with your doctor before starting treatment. An electrocardiogram (ECG) will be required before initiating this medication and periodically during treatment. Discuss the details with your doctor.
To avoid potential interactions, do not consume grapefruit or grapefruit juice while taking this medication.
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 count, which could affect fertility. If you have concerns about fathering a child, discuss this with your doctor.
If you are pregnant, planning to become pregnant, or breastfeeding, consult with your doctor to weigh the benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe hypotension (very low blood pressure)
- Bradycardia (very slow heart rate)
- Intraventricular conduction disturbances (e.g., QRS widening)
- AV block
- Ventricular tachycardia or fibrillation
- Asystole
- Convulsions
- Somnolence
- Coma
What to Do:
Call 911 or your local emergency number immediately. For poison control, call 1-800-222-1222. Treatment is supportive and symptomatic, including gastric lavage, activated charcoal, IV fluids, vasopressors for hypotension, atropine for bradycardia, and potentially temporary pacing. Defibrillation may be needed for ventricular arrhythmias. Hemodialysis is not effective.
Drug Interactions
Contraindicated Interactions
- Ritonavir (significant increase in propafenone levels)
- Quinidine (in CYP2D6 extensive metabolizers, may convert to poor metabolizer phenotype, increasing propafenone levels)
- Other Class I antiarrhythmics (e.g., flecainide, disopyramide) due to additive proarrhythmic effects
Major Interactions
- Digoxin (propafenone increases digoxin levels, monitor digoxin levels)
- Warfarin (propafenone may potentiate anticoagulant effect, monitor INR)
- Beta-blockers (e.g., metoprolol, propranolol - propafenone inhibits CYP2D6, increasing beta-blocker levels; additive negative inotropic/chronotropic effects)
- Local anesthetics (e.g., lidocaine - additive CNS and cardiac effects)
- Cimetidine (increases propafenone levels)
- Amiodarone (may increase propafenone levels and proarrhythmic risk)
- SSRIs (e.g., fluoxetine, paroxetine - potent CYP2D6 inhibitors, may increase propafenone levels)
- Macrolide antibiotics (e.g., erythromycin - may inhibit CYP3A4, increasing propafenone levels)
Moderate Interactions
- Grapefruit juice (may inhibit CYP3A4, increasing propafenone levels)
- Rifampin (induces CYP enzymes, may decrease propafenone levels)
- Phenobarbital, Phenytoin (induce CYP enzymes, may decrease 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: Prior to initiation of therapy.
Serum Electrolytes (Potassium, Magnesium)
Rationale: Electrolyte imbalances can exacerbate proarrhythmic effects. Correct any abnormalities before starting therapy.
Timing: Prior to initiation of therapy.
Renal Function (BUN, Creatinine)
Rationale: To assess kidney function, as metabolites are renally excreted.
Timing: Prior to initiation of therapy.
Hepatic Function (ALT, AST, Bilirubin)
Rationale: To assess liver function, as propafenone is extensively metabolized by the liver.
Timing: Prior to initiation of therapy.
Blood Pressure and Heart Rate
Rationale: To establish baseline cardiovascular status.
Timing: Prior to initiation of therapy.
Routine Monitoring
Electrocardiogram (ECG) - PR, QRS, QT intervals
Frequency: Regularly, especially during dose titration and periodically thereafter (e.g., monthly for first few months, then every 3-6 months).
Target: QRS duration should not increase by more than 25% from baseline. PR and QT intervals should be monitored for significant prolongation.
Action Threshold: If QRS duration increases by >25% or PR/QT intervals prolong significantly, consider dose reduction or discontinuation. New or worsening arrhythmias.
Serum Electrolytes (Potassium, Magnesium)
Frequency: Periodically, especially if patient is on diuretics or has conditions predisposing to electrolyte imbalance.
Target: Within normal limits.
Action Threshold: Correct imbalances promptly.
Blood Pressure and Heart Rate
Frequency: Regularly.
Target: Within patient's normal range.
Action Threshold: Significant hypotension or bradycardia.
Hepatic Function (ALT, AST)
Frequency: Periodically, especially in patients with pre-existing hepatic impairment or signs of liver dysfunction.
Target: Within normal limits.
Action Threshold: Significant elevation of liver enzymes.
Signs and Symptoms of Proarrhythmia
Frequency: Continuously (patient education is key).
Target: Absence of new or worsening arrhythmias.
Action Threshold: New or more frequent palpitations, syncope, chest pain, shortness of breath.
Symptom Monitoring
- New or worsening palpitations
- Dizziness or lightheadedness
- Syncope (fainting)
- Chest pain
- Shortness of breath
- Swelling in ankles or feet
- Unusual fatigue
- Nausea or vomiting
- Changes in vision
Special Patient Groups
Pregnancy
Propafenone is Pregnancy Category C. Animal studies have shown adverse effects on the fetus, but there are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Potential for teratogenicity observed in animal studies at high doses. Human data are limited.
Second Trimester:
Risk of fetal bradycardia or other arrhythmias, especially with high maternal doses.
Third Trimester:
Risk of fetal bradycardia or other arrhythmias, and potential for neonatal effects if used close to delivery.
Lactation
Propafenone and its active metabolite are excreted into breast milk. The amount is small, but potential for adverse effects on the infant (e.g., bradycardia, arrhythmias) exists. Use with caution; monitor breastfed infant for signs of adverse effects (e.g., bradycardia, feeding difficulties, lethargy). Consider alternative agents or temporary discontinuation of breastfeeding.
Infant Risk:
L3 (Moderate risk - compatible with caution)
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Use is generally not recommended due to the risk of proarrhythmia and lack of sufficient data. If used, it should be under strict specialist supervision with careful monitoring.
Geriatric Use
Elderly patients may be more sensitive to the effects of propafenone due to age-related decreases in renal and hepatic function, and potential for polypharmacy. Start with lower doses and titrate slowly. Monitor ECG, blood pressure, and renal/hepatic function closely. Increased risk of adverse effects, including proarrhythmia.
Clinical Information
Clinical Pearls
- Propafenone is a Class Ic antiarrhythmic with a significant black box warning against use in patients with structural heart disease due to increased mortality risk.
- Dose titration should be done slowly (every 3-4 days) to allow for steady-state concentrations and to assess ECG changes (especially QRS widening).
- Genetic polymorphism of CYP2D6 significantly impacts propafenone metabolism and half-life. Extensive metabolizers require higher doses and have shorter half-lives than poor metabolizers.
- Monitor ECG for QRS widening (>25% increase from baseline) as a sign of excessive sodium channel blockade, which may necessitate dose reduction or discontinuation.
- Correct hypokalemia and hypomagnesemia prior to and during propafenone therapy to minimize proarrhythmic risk.
- Propafenone has weak beta-blocking activity, which can contribute to bradycardia or bronchospasm in susceptible individuals.
- Avoid concomitant use with other Class I antiarrhythmics due to additive proarrhythmic effects.
Alternative Therapies
- Flecainide (another Class Ic antiarrhythmic)
- Amiodarone (Class III antiarrhythmic)
- Sotalol (Class III antiarrhythmic with beta-blocking properties)
- Dofetilide (Class III antiarrhythmic)
- Dronedarone (Class III antiarrhythmic)
- Beta-blockers (e.g., metoprolol, atenolol)
- Calcium channel blockers (e.g., diltiazem, verapamil)
- Catheter ablation (non-pharmacological)
Cost & Coverage
Average Cost:
$30 - $150 per 30 tablets (225mg)
Generic Available:
Yes
Insurance Coverage:
Tier 2 or Tier 3 (for generic)
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 medical attention. When seeking help, be prepared to provide details about the medication, including the amount taken and the time it happened, to facilitate prompt and effective treatment.