Health Guide

Propafenone (By mouth)

Propafenone Hydrochloride (proe-PA-fen-one hye-droe-KLOR-ide)

Treats or prevents atrial fibrillation (heart rhythm problems or arrhythmias).

Brand Name(s):

Rythmol SR

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

Do not use this medicine if you have had an allergic reaction to propafenone. Your doctor will determine if this medicine is right for you, because this medicine should not be used if you have certain heart or heart rhythm problems, such as Brugada syndrome, heart failure, AV block, or sick sinus syndrome (unless you have an artificial pacemaker). Do not use this medicine if you have very low blood pressure, mineral imbalance (such as low salt levels in your blood), or lung disease (such as severe COPD).

How to Use This Medicine:

Long Acting Capsule, Tablet

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
  • Swallow the extended-release capsule whole. Do not crush, break, or chew it.
  • You may need to carry identification stating that you are using propafenone. Ask your doctor about this.
  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • There are many other drugs that can interact with propafenone. Make sure your doctor knows about all other medicines you are using, especially digoxin (Lanoxin®), ketoconazole (Nizoral®), ritonavir (Norvir®), saquinavir (Fortovase®, Invirase®), other medicines for heart rhythm problem (such as amiodarone, disopyramide, dofetilide, lidocaine, quinidine, Cardioquin®, Cordarone®, Norpace®, Quinaglute®, Tikosyn®), blood pressure medicine (such as atenolol, metoprolol, propranolol, Tenormin®), or a blood thinner (such as warfarin, Coumadin®, Jantoven®).
  • Make sure your doctor knows if you are also using cimetidine (Tagamet®), rifampin (Rifadin®, Rimactane®), or orlistat (Xenical®). Tell your doctor if you use certain antibiotics (such as azithromycin, clarithromycin, erythromycin, Zithromax®), medicine for depression (such as amitriptyline, desipramine, nortriptyline, paroxetine, sertraline, Elavil®), or medicine for mental illness (such as prochlorperazine, promethazine, Compazine®, Phenergan®, Mellaril®, Trilafon®).
  • Tell your doctor if you smoke.
  • Do not eat grapefruit or drink grapefruit juice while you are using this medicine.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, myasthenia gravis, lupus, or breathing problems. Tell your doctor if you have heart disease or have recently had a heart attack. Make sure your doctor knows if you have a pacemaker.
  • This medicine affects your heart rhythm, so it could cause new or worse rhythm problems. Call your doctor if your symptoms do not improve or if they get worse.
  • This medicine can lower the number of white blood cells you have, so you might be more likely to get an infection. If you can, avoid people who are sick. Check with your doctor if you have a fever, chills, cough, or sore throat.
  • Call your doctor if you have severe diarrhea, vomiting, sweating, loss of appetite, or thirst. These problems can change the mineral levels in your blood and lead to side effects from this medicine.
  • This medicine may decrease the amount of sperm men make. Talk to your doctor if you have concerns about this.
  • This medicine may make you dizzy or drowsy. Avoid driving, using machines, or doing anything else that could be dangerous until you know how this medicine affects you.
  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments. You might need to have an electrocardiogram (ECG) or a blood test for your ANA level (antinuclear antibody).

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Chest pain, or worsening of heart rhythm problem
  • Fever, chills, cough, stuffy or runny nose, sore throat, and body aches
  • Lightheadedness, dizziness, or fainting
  • Swelling in your hands, ankles, or feet, weight gain
  • Trouble breathing, cold sweat, bluish-colored skin
  • Unexpected heartbeat changes, fast or slow heartbeat
  • Unusual bleeding, bruising, or weakness

If you notice these less serious side effects, talk with your doctor:

  • Anxiety
  • Metallic or bitter taste
  • Nausea, constipation

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 7/4/2018
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