1 What is Rythmol?

Brand: Rythmol, Rythmol SR

Generic: Propafenone

Rythmol is a prescription-only antiarrhythmic drug used to prevent recurrence of abnormal heart rhythms such as atrial fibrillation (AF).

Consult your doctor about using this drug as it may cause serious problems in some patients. It is available as:

  • Extended Release capsule
  • Tablet

2 What to Know Before Using

Before using Rythmol, you must know all about the risks and complications associated with it. Together with your doctor, you can decide whether the medication will provide you more goods than the harms.

Here are some factors to be considered before deciding to use this medicine:

  • Allergies: Inform your doctor about the allergies you have, such as to this medication, other medications, or to foods, dyes, or preservatives.
  • Pediatric: It’s not clear if propafenone is safe or effective for use in children.
  • Geriatric: It may be used in elderly after assessing the risks and benefits.
  • Pregnancy: Propafenone falls under category C for all trimesters, meaning that due to lack of sufficient studies, it’s not clear if this medication is safe for use in pregnancy.
  • Breastfeeding: Consult your doctor before using this drug if you are breastfeeding.
  • Drug Interactions: Taking two medicines together can be harmful due to possible interactions. In other cases, even if there is a possible interaction between two medicines your doctor may advise you to take them together after adjusting the dose or issuing precautions. Here is a list of the medicines which in general are not recommended to be used with propafenone. Inform your doctor if you are using any of these medicines:

        o Amifampridine
        o Bepridil
        o Cisapride
        o Dronedarone
        o Fluconazole
        o Ketoconazole
        o Levomethadyl
        o Mesoridazine
        o Nelfinavir
        o Pimozide
        o Piperaquine
        o Posaconazole
        o Ritonavir
        o Saquinavir
        o Sparfloxacin
        o Terfenadine
        o Thioridazine
        o Tipranavir
        o Ziprasidone

Though usually not recommended, your doctor may decide, after adjusting dose or frequency of one or both medicines, to use this medicine with any of the following medicines:

        o Amitriptyline
        o Apomorphine
        o Artemether
        o Astemizole
        o Azithromycin
        o Bretylium
        o Bupropion
        o Chloroquine
        o Chlorpromazine
        o Ciprofloxacin
        o Citalopram
        o Digoxin
        o Disopyramide
        o Dofetilide
        o Domperidone
        o Duloxetine
        o Gatifloxacin
        o Haloperidol
        o Halothane
        o Isoflurane
        o Lidocaine
        o Methadone
        o Metronidazole
        o Mifepristone
        o Octreotide
        o Prochlorperazine
        o Promethazine
        o Propafenone
        o Quinine
        o Sertraline
        o Sulfamethoxazole
        o Tacrolimus
        o Tizanidine
        o Trazodone
        o Trifluoperazine
        o Trimethoprim
        o Voriconazole
        o Zolmitriptan
        o Zotepine

Rarely and only when absolutely needed, this medicine may be used with the following medicines even if using them together may put you at risk of certain side effects. In such cases, you may have to take the adjusted dose or change the frequency of intake.

        o Cyclosporine
        o Rifampin
        o Rifapentine
        o Theophylline
        o Tolterodine
        o Warfarin

  • Other Interactions: Taking your medicine together with certain foods or items such as alcohol or tobacco may cause undesirable interactions. Talk to your doctor to know if using this medicine with food, alcohol, or tobacco is safe. Propafenone should not be used with any of the following:

        o Grapefruit Juice
        o Tobacco

  • Medical Problems: Certain medical conditions might influence the effects (both positive and adverse) and action of propafenone. DO NOT forget to inform your doctor about the following conditions:

        o Asthma or Bronchitis or Emphysema (May worsen breathing problems)
        o AV block, with no pacemaker
        o Bradycardia
        o Lung disease (severe obstructive pulmonary disease)
        o Brugada syndrome
        o Cardiogenic shock
        o Heart failure
        o Hypotension
        o Mineral deficiency
        o Sick sinus node syndrome with no pacemaker (Do not use propafenone)
        o Disorders of blood or bone marrow (agranulocytosis, granulocytopenia)
        o Coronary artery disease
        o Abnormal heart rhythms (QT prolongation)
        o Myasthenia gravis (abnormally weak muscles)
        o Torsade de pointes
        o Ventricular fibrillation
        o Tachycardia (Use cautiously)
        o Kidney disease or Liver disease (Use cautiously)
        o Exercise extra caution if you have a permanent pacemaker

3 Proper Usage

To use Rythmol properly, you must follow all instructions given by your doctor. Here are some points to watch for:

  • Use this medication only as directed.
  • Read the patient information leaflet carefully and follow accordingly. For any query, consult your doctor.
  • Do not break, chew or crush extended-release capsules. Swallow the entire capsule.
  • You may take propafenone with, before or after food.
  • Do not skip the dose even if dosing times may seem inappropriate. For instance taking a medicine three times a day means you have to take the medicine every 8 hours. Manage your time accordingly. You may also carry a medical identification card indicating the use of propafenone.


For best results, follow your doctor to know what amount of medicine you should take in a single dose. The doses of a medicine can differ according to the conditions for which it is being prescribed. Remember your doses can differ. Consult your doctor if you have anything to ask. The doses for atrial fibrillation are:

Extended-release capsules

  • Adults: Initially 225 milligrams (mg) every 12 hours. The doses may be later adjusted but do not take more than 425 mg every 12 hours.
  • Children: Your doctor will decide the use and dose.


  • Adults: 150 milligrams (mg) every 8 hours. The doses may be later adjusted.
  • Children: Your doctor will decide the use and dose.

Missed Dose:

Take your missed dose once you remember but avoid it if it’s time to take your next dose, and follow your normal dosing schedule. Avoid taking double doses to make up for the missed dose.


  • Store in a closed container at room temperature.
  • Keep away from heat, moisture, and direct light.
  • Do not freeze.
  • Keep away from children.
  • Discard any unused or expired medicines.

4 Precautions to Take

In using Rythmol, you must be careful and take some precautions as advised by your doctor. Your progress should be regularly monitored to determine if you are responding to the treatment. Remember:

  • Propafenone can result in heart rhythm conditions like PR, QRS, or QT prolongation.
  • Call your doctor if your symptoms persist or worsen. Seek immediate medical help if these symptoms (probably of heart failure) appear:

        o Chest pain
        o Rapid shallow breath
        o Swollen hands, ankles, or feet
        o Weight gain

  • Propafenone can temporarily reduce white blood cell count making you more susceptible to infections. Therefore, you:

        o May avoid sick people, as far as possible.
        o Need to visit your doctor immediately if you develop fever or chills, cough or hoarseness, lower back pain, or pain during urination.

  • Propafenone may interfere with some medical test results. So, inform your doctor about this.
  • Take special care while driving or using machines as propafenone may cause dizziness.
  • Do not abruptly discontinue this medicine without consulting your doctor.
  • Propafenone can reduce your sperm count. Consult your doctor.
  • Avoid grapefruit or its juice while taking propafenone.
  • Consult your doctor about using other prescription or nonprescription medicines and herbal or vitamin supplements while taking propafenone.

5 Potential Side Effects

Make sure you meet with your doctor in using Rythmol to avoid unwanted potential side effects.

Consult your doctor immediately if you experience any of the following side effects:

Less common:


Mild and non-serious side effects usually go away on their own without requiring medical intervention. You may also ask your doctor to learn more about how you may prevent or reduce the side effects.

Talk to your doctor if the side effects persist or worry you, including:

More common:

  • Taste alterations including bitter or metallic taste

Less common:

The side effects of the medicine are not limited to the ones listed above. Call your doctor immediately if you experience any side effects that are uncommon or worry you. To report side effects to the FDA, contact at 1-800-FDA-1088.