7 Tikosyn (Dofetilide) Side Effects You Should Know About

Atrial fibrillation (AFib) and atrial flutter are health conditions caused by abnormal electrical signals in your heart. AFib is the most common type of arrhythmia (irregular heartbeat) —- it’s estimated that in the year 2030, it will affect over 12 million people in the U.S. If left untreated, these arrhythmias can lead to serious problems, such as heart failure or stroke.

Thankfully, there are treatments available for these conditions. Tikosyn (dofetilide) is an oral capsule that helps restore and maintain a normal heart rhythm. But what side effects should you be aware of before taking it? 

Tikosyn side effects at a glance

Like all medications, Tikosyn can cause side effects. Some are mild, while others are more serious. Here’s an overview of the Tikosyn side effects reported in clinical studies. 

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Keep in mind that everyone responds to medication differently. So you may experience side effects that aren’t listed below.

Common side effects: 

• Headache

• Chest pain

• Dizziness

• Respiratory tract infections

• Shortness of breath

• Nausea 

• Flu-like symptoms

• Trouble sleeping

• Back pain 

• Stomach pain

• Diarrhea

• Rash

Rare but serious side effects:

• Abnormal heart rhythms (including QT prolongation and Torsade de Pointes)

• Heart block

• Facial paralysis

• Angioedema (swelling of the face and mouth)

• Stroke

• Liver damage

• Heart attack

Let’s take a closer look at seven Tikosyn side effects and what you can do to manage them. 

1. Headache

Headache is one of the most common side effects caused by medications, and Tikosyn is no exception. Headaches often go away on their own. But staying hydrated and doing breathing exercises may help lessen discomfort.

If needed, an over-the-counter (OTC) pain medication, such as acetaminophen (Tylenol), may also help. But you should avoid taking nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Motrin, Advil) unless your cardiologist OKs it.

2. Dizziness

Another common Tikosyn side effect is dizziness. In most cases, you’ll receive your first few days of Tikosyn in a hospital. So you’ll have support staff on hand to help you get out of bed and move around safely if you’re feeling dizzy.

If you experience dizziness once you’re at home, find a safe place to sit or lie down until it passes. Some other things to do include:

• Drink water.

• Eat a small snack.

• Check your blood glucose (sugar) levels if that’s part of your normal routine.

• Check your blood pressure.

If dizziness doesn’t improve or worsens, call your cardiac care team for guidance. Take note of when dizziness occurs in relation to your Tikosyn dose or if you notice any potential dizziness triggers throughout the day. This can help your care team pinpoint the cause.

Dizziness along with chest pain, an irregular heartbeat, or trouble breathing may be a sign of a more serious issue. In this case, call 911 or go to the nearest ER.

3. Chest pain

Chest pain can also happen while you’re taking Tikosyn. Chest pain from Tikosyn may be mild and go away on its own, but it’s still a good idea to let your cardiac care team know if you experience this side effect.

You should seek immediate medical care if you have chest pain along with any of the following symptoms:

• Trouble breathing

• Pain in your jaw, arm, or back

• Fever

• Sweating

• Fast heartbeat

• Weakness

4. Nausea and stomach pain

Nausea and stomach pain are both possible Tikosyn side effects. Nausea will often go away on its own. You can try managing it at home by:

• Drinking plenty of fluids

• Eating frequent, small meals instead of fewer large meals 

• Following the BRAT diet for a short time (bananas, rice, applesauce, toast)

• Trying natural remedies such as peppermint tea or ginger candy

Sometimes, you may also experience stomach pain when you feel nauseous. Stomach pain isn’t always an emergency. But if you have sudden or severe stomach pain, especially with symptoms such as a fever or bleeding, seek emergency medical care. 

5. Respiratory infection or flu-like symptoms

Respiratory tract infections and flu-like symptoms were both Tikosyn side effects reported in clinical studies. This can include cough, runny nose, and congestion. Chills, body or muscle aches, and fever are also possible.

These symptoms usually go away on their own over time. But if they worsen or don’t improve, let your healthcare team know. They can help determine if an OTC or prescription medication may help. It’s best to get your prescriber's OK before taking an OTC cough or cold treatment, as some ingredients can affect your heart and may not be safe for you.

6. Trouble breathing

Trouble breathing is another possible Tikosyn side effect. It may be associated with respiratory infection or flu-like symptoms. Or, it can happen on its own.

In some cases, feeling short of breath isn’t anything to worry about. But it can also be a sign of a more serious issue, especially if other symptoms are present, such as:

• Blue fingertips or lips

• Chest pain

• Dizziness

• Fever

• Swelling in your face, hands, or feet 

It’s best to let your cardiac care team know if you’re having trouble breathing while you’re taking Tikosyn. But if you also have any of the above symptoms, call 911 or seek immediate medical care.

7. Serious heart problems

Tikosyn treats irregular heart rhythms. But its most serious side effect is that it can cause them, too. Tikosyn can cause what’s known as long QT syndrome in some people. If this isn’t addressed, it can develop into a life-threatening arrhythmia called Torsade de Pointes.

This rare Tikosyn side effect is the reason why the medication is usually started in the hospital. That way, your cardiac care team can monitor your heart function and address any heart problems as they arise. This includes lowering your Tikosyn dose or stopping treatment altogether.

While Torsade de Pointes can happen to anyone, there are some known risk factors, including:

• Low potassium or magnesium levels

• Older age

• Female gender

• History of long QT caused by medication

• Kidney problems

Drug interactions can also raise the risk of this side effect. You should talk to your cardiac care team before you make any changes to the medications you take, including OTC products and supplements. They can make sure the change won’t affect your Tikosyn levels.

When should you seek medical care for Tikosyn side effects?

Many Tikosyn side effects are mild and should go away on their own. Since you’ll likely be under medical supervision when you start taking Tikosyn, let your care team know how you’re feeling. They can make sure there isn’t a serious reason for your symptoms and suggest options to help you feel better.

Once you’re at home, check in with your care team about any side effects that are bothersome or worsening. And make sure to get their OK before taking an OTC treatment to help.

If at any point you have chest pain, trouble breathing, or notice changes in your heartbeat, reach out to your cardiac care team right away. If any Tikosyn side effects seem severe or life-threatening, seek emergency care.

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Written by:

Emilie White, PharmD

Emilie White is a clinical pharmacist with over a decade of hospital pharmacy experience. Her professional areas of interest include critical care as well as infectious and autoimmune diseases.

Edited by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

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