Flecainide (brand name Tambocor) is used to treat irregular heartbeats (arrhythmias), maintain a normal heart rate or slow an overactive heart. It relaxes the heart and improves its pumping action.

When should it be used?

Flecainide comes in tablets and is usually taken twice a day. Take with food or milk if it causes stomach upset.

This medication is usually started in the hospital, where your response to it can be closely monitored by your doctor.

Your prescription label tells you how much to take at each dose — follow these instructions carefully and ask your doctor or pharmacist to explain any part that you do not understand.

This medication works best when there is a constant level in your body. Therefore, it is important that you take it every 12 hours. Try to take you r doses at the same times each day. NEVER skip doses or take less or more of the medication than your doctor prescribes. Even if you feel well, NEVER stop taking this medication without consulting your doctor.

Ask your pharmacist any questions you have about refilling your prescription.

What special instructions should I follow while using this drug?

  • Tell your healthcare provider about ALL medications and over-the-counter medications, vitamins and supplements you take.
  • Tell your doctor if you had a recent heart attack or if you have kidney or liver disease, a pacemaker or congestive heart failure.
  • Keep all appointments with your doctor and the lab so your doctor knows how the medication is working.
  • Do not drive a car or operate machinery until you know how this drug affects you. Flecainide can cause dizziness, headaches, fatigue and tremor.
  • Always have enough of this medication on hand. Check your supply before vacations, holidays and other times when you may not be able to get more.
  • Ask your doctor or pharmacist for advice about drinking alcoholic beverages. Alcohol can make the dizziness caused by the medication worse.
  • Do not take this medication if you are pregnant, think you might be pregnant or are breastfeeding.
  • Before any surgical or dental procedure or emergency treatment, tell the doctor or dentist that you are taking this medication.

What should I do if I forgot to take a dose?

Take the missed dose if you remember it within six hours. If you do not remember it until six or more hours after the scheduled time, skip the missed dose and take your next regular dose. Do not take a double dose.

What are the common side effects?

Call your doctor if the following symptoms are persistent or severe:

  • Nausea, vomiting or diarrhea
  • Heartburn, gas
  • Loss of appetite
  • Tremors
  • Blurred vision or seeing "spots"
  • Headache
  • Nervousness or confusion
  • Changes in sleep habits
  • Weakness, muscle aches
  • Sweating
  • Bad taste in the mouth
  • Decreased sex drive or impotence
  • Numbness or swelling of hands or feet
  • Ringing in the ears
  • Swollen lips or tongue
  • Dizziness, faintness

Get up slowly from sitting or lying positions. Also, be careful while doing activities that require you to be alert.

How should I store this drug?

  • Keep flecainide in the container it came in.
  • Store tablets at room temperature.
  • Store it away from heat and direct sunlight.
  • Do not keep flecainide in the bathroom.
  • Keep flecainide out of the reach of children.
  • Never share your medication with anyone.

Never take outdated medications. Some medication prescription labels list an expiration date. If such a date is not on your medication label, or if you are unsure how old a medication is, call your pharmacy.

Call your doctor right away if you have any of these symptoms:

  • Chest pain
  • Irregular heartbeat, fast heartbeat
  • Fainting or feeling faint more often
  • Yellow eyes or skin
  • Feel very tired
  • Memory loss
  • Depression
  • Skin rash
  • Fever of 38°C (100°F) or higher
  • Sore throat
  • Trouble breathing, urinating, walking or talking
  • Other symptoms that cause concern


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