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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Propafenone Hydrochloride
Generic Name
Propafenone Hydrochloride
Active Ingredient
PropafenoneCategory
Other
Salt Form
Hydrochloride
Variants
50
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Propafenone Hydrochloride, you must consult a qualified healthcare professional.
| 225 mg/1 | TABLET, FILM COATED | ORAL | 64380-268 |
| 150 mg/1 | TABLET, FILM COATED | ORAL | 64380-269 |
| 225 mg/1 | CAPSULE, EXTENDED RELEASE | ORAL | 68462-408 |
| 325 mg/1 | CAPSULE, EXTENDED RELEASE | ORAL | 59651-277 |
| 225 mg/1 | TABLET, COATED | ORAL | 63629-1988 |
| 300 mg/1 | TABLET, COATED | ORAL | 63629-1989 |
| 325 mg/1 | CAPSULE, EXTENDED RELEASE | ORAL | 70771-1526 |
| 300 mg/1 | TABLET, COATED | ORAL | 72162-1753 |
| 325 mg/1 | CAPSULE, EXTENDED RELEASE | ORAL | 16571-737 |
+ 38 more variants
Detailed information about Propafenone Hydrochloride
Propafenone is a Class IC antiarrhythmic medication used to treat and prevent serious heart rhythm disorders such as paroxysmal atrial fibrillation and ventricular arrhythmias by stabilizing cardiac cell membranes.
Dosage for propafenone must be highly individualized and carefully titrated by a healthcare provider, typically starting with a low dose and increasing gradually based on clinical response and safety monitoring (ECG changes).
The safety and effectiveness of propafenone in pediatric patients (under 18 years of age) have not been established through large-scale clinical trials. While pediatric cardiologists may occasionally use propafenone off-label for specific pediatric arrhythmias, it is not FDA-approved for this population. Dosing in children, when performed, is usually based on body surface area (mg/m²) and requires extreme caution and monitoring by a specialist in pediatric electrophysiology.
Propafenone is extensively metabolized, but its metabolites are excreted by the kidneys. In patients with significant renal impairment, metabolites may accumulate. While specific GFR-based dosing scales are not always provided in the labeling, healthcare providers typically exercise caution and may prescribe lower doses or longer intervals between doses for patients with stage 3 or 4 chronic kidney disease.
Because propafenone is primarily cleared by the liver, patients with liver disease (such as cirrhosis) will have significantly increased plasma levels of the drug. According to the FDA, the dose should be reduced by approximately 50% to 70% in patients with hepatic impairment. Close monitoring of the ECG for QRS widening or QT prolongation is mandatory in this population.
Older adults may have reduced renal or hepatic function and are often more sensitive to the side effects of antiarrhythmic drugs. Healthcare providers generally start elderly patients at the lower end of the dosing range and titrate more slowly. There is also an increased risk of conduction disturbances (like heart block) in the elderly.
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and return to your regular schedule. Do not double the dose to catch up, as this significantly increases the risk of proarrhythmia or heart block.
An overdose of propafenone is a medical emergency. Symptoms may include severe hypotension (low blood pressure), extreme bradycardia (slow heart rate), widening of the QRS complex on an ECG, ventricular tachycardia, or even cardiac arrest. Non-cardiac symptoms can include seizures and respiratory distress. If an overdose is suspected, call 911 or your local emergency services immediately. Treatment usually involves supportive care, gastric lavage if caught early, and potentially the use of intravenous sodium bicarbonate to reverse the sodium channel blockade.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking this medication without medical guidance, as sudden discontinuation can lead to a 'rebound' of your heart rhythm disorder.
Propafenone is generally well-tolerated, but because it affects the electrical system of the heart and has mild beta-blocking properties, side effects are possible. The most common side effects reported in clinical trials include:
Propafenone is a powerful medication that requires careful management. It is not a 'simple' pill for palpitations; it is a drug that alters the electrical properties of the heart. Patients must be aware that while it prevents certain arrhythmias, it has the potential to cause others. This is known as the proarrhythmic effect. It is essential to maintain all follow-up appointments and report any changes in your health immediately to your cardiologist.
No FDA black box warnings for Propafenone are currently listed in the same format as drugs like antidepressants; however, the CAST-related Warning is the most critical safety alert associated with this drug. It states that Class IC antiarrhythmics should be reserved for patients with life-threatening ventricular arrhythmias or highly symptomatic supraventricular arrhythmias, and should be avoided in patients with structural heart disease (e.g., post-MI, heart failure) due to an increased risk of mortality.
Certain drugs should never be used with propafenone because the risk of a life-threatening interaction is too high. These include:
Propafenone must NEVER be used in patients with the following conditions, as the risks significantly outweigh any potential benefits:
Propafenone is classified as FDA Pregnancy Category C (under the older system, now integrated into the 'Pregnancy and Lactation Labeling Rule'). Animal studies have shown some evidence of fetal harm at high doses, but there are no adequate, well-controlled studies in pregnant women. Propafenone should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. If used, the mother and fetus should be monitored closely for heart rate changes. It is generally avoided in the first trimester unless absolutely necessary for maternal stability.
Propafenone is known to be excreted in human breast milk. Because of the potential for serious adverse reactions in nursing infants (such as changes in heart rhythm), a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. If a mother must take propafenone while breastfeeding, the infant should be monitored for bradycardia or other signs of cardiac distress.
As previously noted, propafenone is not FDA-approved for use in children. The pharmacokinetics in children are not well-defined, and the risk of proarrhythmia in a developing heart is a significant concern. Use in this population is restricted to specialized pediatric electrophysiologists treating refractory (difficult to treat) arrhythmias.
Propafenone is a Class IC antiarrhythmic agent with local anesthetic effects. Its primary mechanism is the potent inhibition of the voltage-gated fast sodium channels (Nav1.5). By binding to these channels in their active and inactive states, it slows the inward sodium current during Phase 0 of the cardiac action potential. This results in a marked decrease in the rate of rise of the action potential (Vmax) and a slowing of conduction velocity throughout the myocardium.
Uniquely, propafenone is a racemic mixture of (S)- and (R)-enantiomers. The (S)-enantiomer possesses significant beta-adrenergic blocking activity, while both enantiomers contribute to the sodium channel blockade. This 'dual-action' helps in suppressing both the triggers (via beta-blockade) and the pathways (via sodium channel blockade) of arrhythmias.
The electrophysiological effects of propafenone manifest as a widening of the PR interval and the QRS duration on the surface ECG. It has a negligible effect on the QT interval unless very high doses are reached. The onset of action for the oral immediate-release form is typically 1 to 3.5 hours, with the peak effect corresponding to the Tmax. The duration of effect is dependent on the individual's metabolic rate but generally lasts 8 to 12 hours for IR and up to 24 hours for SR formulations.
Common questions about Propafenone Hydrochloride
Propafenone is primarily used to treat and prevent certain types of irregular heartbeats, known as arrhythmias. It is specifically indicated for paroxysmal atrial fibrillation (PAF) and paroxysmal supraventricular tachycardia (PSVT) in patients who do not have structural heart disease. Additionally, it is used to treat life-threatening ventricular arrhythmias, such as sustained ventricular tachycardia. By stabilizing the electrical activity in the heart, it helps maintain a normal, steady rhythm. It is often prescribed when other treatments have not been effective or are not suitable for the patient.
The most frequently reported side effect of propafenone is a persistent metallic or bitter taste in the mouth, which affects many patients shortly after starting the drug. Other common side effects include dizziness, lightheadedness, nausea, and blurred vision. Some patients may also experience constipation, fatigue, or a mild headache. While these are often manageable, they should be reported to a doctor if they become bothersome. More serious side effects, though less common, include the development of new or worsening heart rhythm problems.
It is generally advised to limit or avoid alcohol while taking propafenone. Alcohol can act as a trigger for atrial fibrillation and other heart rhythm disorders, which may counteract the benefits of the medication. Furthermore, alcohol can increase the risk of dizziness and lightheadedness when combined with propafenone's effects on the heart and blood pressure. Some studies suggest that alcohol may also interfere with the way the liver processes certain medications. Always consult your healthcare provider regarding what amount of alcohol, if any, is safe for your specific heart condition.
Propafenone is not considered first-line therapy during pregnancy and should only be used if the potential benefit to the mother outweighs the potential risk to the fetus. It is classified as Category C, meaning animal studies have shown some risk, but human data is limited. The drug does cross the placenta and could theoretically affect the fetal heart rhythm. If you are pregnant or planning to become pregnant, your cardiologist will likely explore other options or monitor you very closely if propafenone is deemed necessary. Breastfeeding is also generally discouraged while taking this medication as it passes into breast milk.
For the immediate-release tablets, the drug typically begins to have an effect within 1 to 3 hours of the first dose, reaching its peak concentration in the blood around 2 to 3 hours. However, it may take several days of consistent dosing (usually 3 to 4 days) for the drug to reach a 'steady state' in your system where the full antiarrhythmic effect can be evaluated. The extended-release capsules take slightly longer to reach peak levels, usually between 3 and 8 hours. Your doctor will monitor your heart rhythm during this initial period to ensure the medication is working correctly.
No, you should never stop taking propafenone suddenly without consulting your healthcare provider. Abruptly discontinuing an antiarrhythmic medication can lead to a 'rebound' effect, where your heart rhythm disorder returns more frequently or more severely than before. In some cases, stopping the drug suddenly can trigger a dangerous or life-threatening arrhythmia. If the medication needs to be stopped due to side effects or a change in treatment plan, your doctor will provide a specific schedule to gradually reduce the dose or transition you to another therapy safely.
If you miss a dose of propafenone, you should take it as soon as you remember. However, if it is nearly time for your next scheduled dose, you should skip the missed dose and simply take the next one at the regular time. It is vital that you do not take two doses at once to make up for a missed one, as doubling the dose can lead to toxicity and dangerous changes in your heart's electrical rhythm. Setting a daily alarm or using a pill organizer can help ensure you take this medication consistently at the same times each day.
Weight gain is not a commonly reported side effect of propafenone in clinical trials. However, because propafenone can occasionally cause or worsen heart failure in susceptible individuals, sudden weight gain (such as 3-5 pounds in a week) accompanied by swelling in the ankles or shortness of breath should be taken very seriously. This type of weight gain is usually due to fluid retention rather than body fat. If you notice rapid weight gain or significant swelling while taking this medication, you should contact your healthcare provider immediately for an evaluation of your heart function.
Propafenone has many significant drug interactions, so it must be used cautiously with other medications. It can significantly increase the levels of digoxin and warfarin in your blood, requiring dose adjustments of those drugs. It also interacts with many common antidepressants (like fluoxetine) and certain antibiotics, which can cause propafenone levels to rise to dangerous levels. Because of these risks, it is essential to provide your doctor and pharmacist with a complete list of all prescription drugs, over-the-counter medicines, and herbal supplements you are currently taking.
Yes, propafenone is available as a generic medication in both immediate-release tablet and extended-release capsule forms. The generic versions are bioequivalent to the brand-name versions, such as Rythmol and Rythmol SR, meaning they contain the same active ingredient and work the same way in the body. Generic propafenone is typically much less expensive than the brand-name versions and is covered by most insurance plans. When switching between brand and generic, or between different generic manufacturers, your doctor may occasionally want to check an ECG to ensure the effect remains consistent.
Other drugs with the same active ingredient (Propafenone)
> Warning: Stop taking Propafenone and call your doctor immediately if you experience any of these symptoms. These may indicate a life-threatening reaction or a dangerous change in your heart rhythm.
With prolonged use, some patients may develop chronic fatigue or a persistent change in taste. There is also a risk of developing conduction system disease, such as bundle branch blocks or higher-grade AV blocks, which may require a dose reduction or the placement of a pacemaker. Regular ECG monitoring is essential for anyone on long-term propafenone therapy to ensure the electrical intervals (like the QRS duration) remain within safe limits.
Propafenone carries a significant warning based on the Cardiac Arrhythmia Suppression Trial (CAST).
The CAST Warning Summary: In a large clinical trial (CAST), patients with a recent heart attack (myocardial infarction) who were treated with Class IC antiarrhythmic drugs (like encainide or flecainide) had a higher rate of death compared to those who received a placebo. While propafenone was not specifically in the CAST trial, it belongs to the same class. Therefore, propafenone should not be used in patients with structural heart disease, such as those who have had a heart attack or those with heart failure, as the risk of death may outweigh the benefits of rhythm control.
Report any unusual symptoms to your healthcare provider. Your doctor will likely perform regular blood tests and ECGs to monitor for these side effects.
If you are taking propafenone, your healthcare provider will require regular monitoring, which may include:
Propafenone can cause dizziness, blurred vision, or fatigue, especially when first starting the medication. You should not drive or operate heavy machinery until you know how the drug affects you.
Alcohol should be consumed with extreme caution. Alcohol itself can be a trigger for atrial fibrillation ('Holiday Heart Syndrome') and may enhance the sedative or dizzying effects of propafenone. Discuss your alcohol consumption with your doctor.
Do not stop taking propafenone abruptly. Stopping the medication suddenly can cause your arrhythmia to return, sometimes more severely than before. If the drug needs to be stopped, your doctor will provide a tapering schedule or transition you to a different medication.
> Important: Discuss all your medical conditions, especially any history of heart attack, asthma, or liver disease, with your healthcare provider before starting Propafenone.
Propafenone does not typically interfere with standard laboratory tests, but it can affect the results of an exercise stress test by altering the heart's electrical response to exertion. Always inform the technician performing a stress test that you are taking this medication.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking. A complete 'brown bag' review of your medications is the safest way to prevent interactions.
In these cases, a healthcare provider must perform a careful risk-benefit analysis:
There is no widespread evidence of cross-sensitivity between propafenone and other classes of drugs, but patients who have had a severe allergic reaction (anaphylaxis) to other local anesthetics or other Class IC antiarrhythmics (like flecainide) should be monitored closely for signs of hypersensitivity.
> Important: Your healthcare provider will evaluate your complete medical history, including recent ECGs and heart imaging (like an echocardiogram), before prescribing Propafenone.
Clinical studies have shown that elderly patients (over 65) may have higher plasma concentrations of propafenone due to age-related declines in liver and kidney function. There is also a higher prevalence of underlying structural heart disease in this age group, which may contraindicate the drug's use. Geriatric patients are at a higher risk of developing conduction disturbances and should be monitored with frequent ECGs during the titration phase.
In patients with impaired kidney function, the metabolites of propafenone can accumulate. While the parent drug is mostly cleared by the liver, these metabolites still possess some biological activity. Patients with a GFR below 30 mL/min should be treated with extreme caution, and dosage should be titrated slowly with frequent clinical assessment.
This is a critical consideration for propafenone. In patients with liver cirrhosis, the bioavailability of propafenone increases significantly, and the half-life is prolonged. The FDA recommends that the dose be reduced to 20-30% of the standard dose in patients with severe hepatic impairment. Failure to adjust the dose in these patients can lead to rapid toxicity.
> Important: Special populations require individualized medical assessment and often more frequent diagnostic testing to ensure safety.
| Parameter | Value |
|---|---|
| Bioavailability | 5% to 50% (Saturable first-pass) |
| Protein Binding | ~97% (Alpha-1-acid glycoprotein) |
| Half-life | 2-10 hrs (Extensive), 10-32 hrs (Poor) |
| Tmax | 2 to 3 hours (IR); 3 to 8 hours (SR) |
| Metabolism | Hepatic: CYP2D6 (Primary), 3A4, 1A2 |
| Excretion | Fecal (53%), Renal (38% as metabolites) |
Propafenone is categorized as a Class IC antiarrhythmic. Other drugs in this class include flecainide and encainide. While they all share sodium channel blocking properties, propafenone is distinguished by its clinically relevant beta-blocking activity.