Propafenone (Rythmol) is a Class 1C antiarrhythmic medication used to treat certain heart rhythm problems, like atrial fibrillation (AFib). But it's not a good choice for people who have structural heart disease, like heart valve issues. Propafenone (Rythmol) is taken by mouth, typically 2 to 3 times a day, depending on whether you're taking the immediate-release (IR) tablets and extended-release (ER) capsules. Some side effects of propafenone (Rythmol) include dizziness, chest pain, and trouble catching your breath.
Prevention of atrial fibrillation (Afib) or atrial flutter
Prevention of paroxysmal supraventricular tachycardia (PSVT) - immediate-release tablets only
Treatment of life-threatening ventricular arrhythmias - immediate-release tablets only
Propafenone (Rythmol) is an antiarrhythmic. It works by blocking sodium channels, which play a major part in your heart's electrical activity. It slows down abnormal electrical activity in your heart to treat abnormal rhythms.
Source:Â DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Less common
fast, irregular, or slow heartbeat
lightheadedness, dizziness, or fainting
shortness of breath
swelling of the feet or lower legs
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Change in taste or bitter or metallic taste
Less common
Blurred vision
dryness of the mouth
headache
nausea or vomiting
skin rash
unusual tiredness or weakness
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Used for different types of irregular heart rhythms
Not known to cause liver damage like some alternatives
Extended-release capsule can be taken twice a day
Available in a lower-cost, generic form
Not for use if you have certain heart conditions such as heart failure or low blood pressure
Multiple side effects; requires close monitoring
Can lower sperm counts in males
Not studied in children
Don't crush, chew, or open propafenone (Rythmol) extended-release capsule. It's meant to slowly release medication in your body, so breaking it can change the way the medication works.
Most people will start off on a lower dose of propafenone (Rythmol). Don't take a higher dose unless you were specifically told to by your provider. Dose changes should happen very gradually, usually after you have been on the previous dose for at least 3 to 5 days (depending on the pill type).
You can take propafenone (Rythmol) with or without food. But taking it with food might help prevent nausea or upset stomach.
Propafenone (Rythmol) can cause some serious side effects, so you'll need to get blood tests and heart tests (such as EKG) on a regular basis.
Let your provider know if you have any conditions that can lead to abnormal electrolyte levels in the blood, like a lot of diarrhea, sweating, vomiting, or if you're eating or drinking less than usual. Abnormal electrolyte levels can raise your risk of having side effects from propafenone (Rythmol).
Avoid grapefruit juice while on propafenone (Rythmol). If you smoke tobacco regularly, talk to your provider before starting this medication since you might have higher risk of side effects.
If you miss a dose of propafenone (Rythmol), don't double-up on the dose since this can lead to more side effects. Just take your next dose at the usual time.
Report any signs of infection to your provider, such as fever, chills, and body aches. You might need lab work to check for low white blood cell counts, which can lead to more infections.
Propafenone (Rythmol) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
If you have ventricular arrhythmias, your provider will only prescribe propafenone (Rythmol) if they think your condition is life-threatening. Studies of a medication similar to propafenone (Rythmol) suggest that though rare, taking propafenone (Rythmol) might raise the risk of death, especially for people who've had recent heart attacks. If you're concerned about the risks of taking propafenone (Rythmol), talk with your heart specialist.
Risk factors: Brugada syndrome | 'Heart block' without a pacemaker | Taking other medications that affect heart rhythm
Propafenone (Rythmol) can cause worsening of abnormal heart rhythms, including rhythms that are too fast (such as ventricular tachycardia or fibrillation) or too slow (such as as 'heart block' or a very slow heart rate). Many of these conditions are life-threatening, so it's important that you follow-up with your provider regularly. Your provider will check your heart rhythm with an electrocardiogram (EKG) before and after you start propafenone (Rythmol) to make sure the medication is working as it should. If you notice an abnormally slow or fast pulse, chest pain or discomfort, weakness, dizziness, or fainting while taking propafenone (Rythmol), get medical help right away.
Risk factors: Taking other medications that affect heart rhythm | Grapefruit juice | Smoking tobacco
Many medications can raise levels of propafenone (Rythmol) in the blood by slowing its breakdown in the liver. When propafenone (Rythmol) levels are too high, you have a greater risk of side effects. Other medications can interact with propafenone (Rythmol) directly and lead to life-threatening abnormal heart rhythms. Be sure to talk to your providers, including your pharmacist, about all the medications you are taking. Don't drink grapefruit juice while taking propafenone (Rythmol). If you smoke tobacco, talk to your provider before starting this medication.
Risk factors: History of heart problems
Propafenone (Rythmol) can cause new or worsening heart failure. Contact your provider right away if you notice symptoms of heart failure such as unexplained weight gain, edema (swelling due to more fluid) in legs or feet, or more shortness of breath especially when you lie down.
Risk factors: Have a heart device like a pacemaker
Taking propafenone (Rythmol) can affect the function of heart devices like defibrillators or pacemakers. Make sure that you get regular checkups to make sure your device is adjusted appropriately while you are on propafenone (Rythmol).
Propafenone (Rythmol) can cause dangerously low white blood cell counts. This usually happens within the first 2 months of therapy, and goes away after you stop taking propafenone (Rythmol). White blood cells are important for your immune system, so you have a higher risk of infection if the counts are low. Call your provider right away if you notice signs of infection like fever, chills, or sore throat.
Risk factors: Liver disease | Kidney disease
Poor liver or kidney function can cause propafenone (Rythmol) to accumulate (build up) in the body, leading to more side effects. If you have liver or kidney problems, your provider might check lab and heart tests more frequently to be safe.
If you have myasthenia gravis, taking propafenone (Rythmol) can make your condition worse. It's always best to check with your provider before starting any new medications.
Propafenone (Rythmol) can cause lower sperm counts. This effect usually goes away after you stop taking propafenone (Rythmol). If you hope to have children, speak with your provider about alternative medications for your condition.
Immediate-release tablets: The typical starting dose is 150 mg by mouth every 8 hours. Your provider will gradually adjust your dose as needed. The maximum dose is 300 mg every 8 hours.
Extended-release capsules (Rythmol SR): The typical starting dose is 225 mg by mouth every 12 hours. Your provider will gradually adjust your dose as needed. The maximum dose is 425 mg every 12 hours.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Problems with electrical activity in the heart in the absence of a pacemaker
Dangerously low blood pressure
Lung conditions that cause breathing problems (e.g., chronic obstructive pulmonary disease or COPD)
Electrolyte levels that are out of balance
Prevention of atrial fibrillation (Afib) or atrial flutter
Prevention of paroxysmal supraventricular tachycardia (PSVT) - immediate-release tablets only
Treatment of life-threatening ventricular arrhythmias - immediate-release tablets only
Prevention of paroxysmal supraventricular tachycardias (PSVT)
Prevention of paroxysmal atrial fibrillation/flutter (PAF)
Prevention of ventricular arrhythmias
To lower the risk of hospitalization from atrial fibrillation (AFib) in adults who have a history of paroxysmal or persistent AFib
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