Propafenone Extended-Release


In this session, we will be discussing the consumer medication information for propafenone extended release, trade name Rythmol SRTM.

What it’s for & How to take

Propafenone extended release is used to treat patients with an abnormal heartbeat. When your heart has an abnormal beat, you are more likely to develop a blood clot. Blood clots may be may get stuck in your legs, lungs, heart or brain which may lead to a life-threatening emergency.

Propafenone extended release may slow down how fast and how strong your heart may beat. By doing this, the abnormal heart beat is decreased. This category of medications helps keep a heartbeat regular and steady.

Propafenone extended release is usually taken every 12 hours. This medication may be taken with or without food, but try to take it the same way each time. Swallow the capsules whole, do not crush or chew them.

Call your doctor if your condition does not get better after starting this medication.

Do not stop taking this medication or change the dose without talking with your doctor. If you forget to take a dose, take it as soon as you remember. If it is near the time of your next dose, skip it and continue with your normal dose time. Do not take a double dose to make up the missed dose.

Most Important Warnings

  • Propafenone extended release should only be used when the abnormal heartbeat is life threatening. Chance of death may be increased when propafenone extended release is taken for a non-life threatening abnormal heartbeat.
  • Propafenone extended release may sometimes worsen the abnormal heartbeat. This medication should be started on a patient when they are in a hospital to make sure they tolerate the side effects. Talk with your doctor about the risks of taking this medication.

Other Warnings & Cautions

  • Rarely, propafenone extended release may cause your heart to beat fast and unsteady. If you feel any severe dizziness or feel like your heart is racing or beating too fast, get medical help right away.
  • Avoid eating grapefruit or drinking grapefruit juice while taking this medication. Grapefruit may increase the level of this medication in your body and cause dangerous side effects.
  • The elderly may be more sensitive to the side effects of this medication, especially the drowsiness and dizziness. The chance of loss of balance and falling is increased.
  • This medication may make you dizzy, drowsy, or blur your vision. Do not drive or do any activity that requires focus and attention until you are sure you can do them safely. Limit alcoholic beverages while taking propafenone extended release.
  • Talk with your doctor about the risks of taking this medication if you are pregnant or might become pregnant. Breastfeeding is not recommended while taking this medication.

Interactions & Side Effects

  • Tell your pharmacist or doctor all your medication allergies so they may determine if propafenone extended release is safe for you to take.
  • Avoid dangerous drug interactions. Some medications, such as water pills, may increase the chance that you have an abnormal heartbeat. Tell your pharmacist or doctor all the other medication you are taking, including over the counter supplements, even if you don’t take them very often.
  • Ask your doctor if this medication is safe to take with your current health conditions. Tell your doctor if you have myasthenia gravis, a history of heart, liver, or kidney disease, any other medical condition or if you have a pacemaker in your heart.
  • While taking propafenone extended-release, you may have a metallic or salty taste in your mouth. You may also feel some nausea, loss of appetite, dizziness, headache, anxiety or constipation. If these or any other unwanted side effects persist, contact your doctor or pharmacist to talk about it with them.
  • Call your doctor right away if you have any severe vomiting, yellowing of your eyes, swelling in the ankles, shortness of breath or signs of infection such as a fever or sore throat.
  • Call emergency 911 if you have any symptoms of a heart attack such as chest and left arm pain, shortness of breath and sweating or if you have symptoms of a stroke such as weakness on one side of your body, slurred speech, sudden vision changes, and confusion.

If you have any questions about what you have heard, contact your pharmacist or doctor. This session does not include all the potential interactions or side effects that this medication may cause. Ask your pharmacist how your medication should be stored and how you should dispose of it when you are done taking it. Do not share your medication with anyone, ever. Remember, this is not meant to replace your counseling session with your pharmacist. In case of overdose, call your local poison control center at 1-800-222-1222.

Updated 7/20