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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Dofetilide 0.25mg
Generic Name
Dofetilide 0.25mg
Active Ingredient
DofetilideCategory
Antiarrhythmic [EPC]
Variants
1
Different strengths and dosage forms
| Strength | Form | Route | NDC |
|---|---|---|---|
| .25 mg/1 | CAPSULE | ORAL | 70010-025 |
Detailed information about Dofetilide 0.25mg
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Dofetilide 0.25mg, you must consult a qualified healthcare professional.
Dofetilide is a potent Class III antiarrhythmic agent used to restore and maintain normal heart rhythm in patients with atrial fibrillation or atrial flutter. Due to its risk of inducing serious arrhythmias, it requires mandatory hospital monitoring during initiation.
The dosing of Dofetilide is highly individualized and is determined by a healthcare provider based on two critical factors: the patient's renal function (calculated creatinine clearance) and their heart's electrical response (the QT interval) as measured on an electrocardiogram (ECG).
For adults with normal kidney function (Creatinine Clearance > 60 mL/min), the standard starting dose is 500 mcg taken twice daily.
If the patient has moderately impaired kidney function, the dose must be reduced to prevent the drug from building up to dangerous levels:
The safety and effectiveness of Dofetilide in pediatric patients (children under the age of 18) have not been established. Clinical trials for Dofetilide primarily focused on adult populations. Therefore, Dofetilide is not currently approved for pediatric use. Healthcare providers will typically explore other antiarrhythmic options or procedures for children with heart rhythm disorders.
As noted above, renal function is the primary determinant of Dofetilide dosing. Healthcare providers calculate a patient's Creatinine Clearance (CrCl) using the Cockcroft-Gault formula. If kidney function declines during treatment, the dose may need to be lowered or the medication stopped entirely. Routine blood tests to monitor kidney function are mandatory for anyone taking this medication.
Since only about 20% of Dofetilide is metabolized by the liver, mild to moderate hepatic (liver) impairment typically does not require a dose adjustment. However, the drug has not been extensively studied in patients with severe hepatic impairment, so healthcare providers use extreme caution in this population.
Elderly patients are more likely to have decreased kidney function, even if their blood creatinine levels appear normal. Healthcare providers are particularly careful when calculating the initial dose for patients over 65 and will monitor their renal function and ECGs closely throughout treatment.
Taking Dofetilide correctly is essential for maintaining a stable heart rhythm and avoiding dangerous side effects.
If you miss a dose of Dofetilide, do not take the missed dose. Simply wait and take your next scheduled dose at the regular time. Never take two doses at once to make up for a missed one. Taking a double dose significantly increases the risk of a life-threatening arrhythmia. If you miss multiple doses, contact your healthcare provider immediately, as you may need to be re-hospitalized to safely restart the medication.
An overdose of Dofetilide is a medical emergency. The primary risk of overdose is a life-threatening heart rhythm called Torsades de Pointes, which can lead to ventricular fibrillation and cardiac arrest.
If an overdose is suspected, call 911 or your local emergency services immediately. Treatment in an emergency setting usually involves continuous ECG monitoring, correcting electrolyte imbalances (like potassium and magnesium), and potentially using medications or a temporary pacemaker to manage the heart rate.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking Dofetilide without direct medical guidance, as stopping the drug can cause your AFib to return.
While Dofetilide is generally well-tolerated when dosed correctly, some patients may experience side effects as their body adjusts to the medication. Common side effects reported in clinical trials include:
These side effects occur in a smaller percentage of patients but are still significant enough to monitor:
Rare but documented side effects include:
> Warning: Stop taking Dofetilide and call your doctor or emergency services immediately if you experience any of these serious symptoms. These may indicate a life-threatening heart rhythm disturbance.
Dofetilide does not typically cause 'cumulative' toxicity like some other antiarrhythmics (such as amiodarone, which can affect the lungs and thyroid over time). However, the long-term risk associated with Dofetilide is the persistent risk of proarrhythmia (the drug causing a new arrhythmia). As patients age, their kidney function naturally declines. If the Dofetilide dose is not adjusted to match this decline, the risk of serious side effects increases significantly over time. Regular, lifelong monitoring of renal function and ECGs is required for as long as a patient is on the drug.
The FDA has issued a Black Box Warning for Dofetilide, which is the most serious type of warning. The warning states that to minimize the risk of induced arrhythmia, Dofetilide must be initiated (or re-initiated if it was stopped) in a setting where there is continuous ECG monitoring and specialized staff who can calculate creatinine clearance and monitor the QT interval. Patients must stay in this facility for a minimum of three days. This warning exists because the risk of Torsades de Pointes is highest during the first few days of treatment. Statistics show that approximately 2-3% of patients may experience this serious arrhythmia during the initiation phase, necessitating immediate medical intervention.
Report any unusual symptoms, no matter how minor they seem, to your healthcare provider immediately. What might seem like a simple stomach bug can lead to electrolyte imbalances that make Dofetilide dangerous.
Dofetilide is a high-alert medication. Because it works by altering the electrical properties of the heart, it has a narrow 'therapeutic window'—meaning the difference between a helpful dose and a dangerous dose is very small. Patients must be committed to strict adherence to the dosing schedule and regular laboratory monitoring. You must never share this medication with others, and you should ensure that all your healthcare providers (including dentists and specialists) know you are taking Dofetilide.
FDA Black Box Warning Summary: Dofetilide must be initiated in a facility that can provide continuous electrocardiographic (ECG) monitoring and cardiac resuscitation for a minimum of three days. This is required to minimize the risk of Torsades de Pointes, a potentially fatal heart rhythm. Healthcare providers must accurately calculate the patient's creatinine clearance (kidney function) before the first dose and monitor the QT interval closely after each of the first several doses. If the QT interval increases too much, the dose must be reduced or stopped.
If you are prescribed Dofetilide, your medical calendar will include several mandatory tests:
Dofetilide itself does not typically cause sedation. However, because it can cause dizziness or fainting (especially if the heart rhythm changes), you should be cautious when driving or operating heavy machinery until you know how the medication affects you. If you feel lightheaded, stop the activity and contact your doctor.
Alcohol should be used with extreme caution. Alcohol can cause dehydration and affect electrolyte balance, both of which increase the risks associated with Dofetilide. Additionally, excessive alcohol is a known trigger for atrial fibrillation (sometimes called 'Holiday Heart Syndrome'), which may counteract the benefits of the medication.
Do not stop taking Dofetilide abruptly unless directed by your doctor. While there isn't a 'withdrawal syndrome' like with some medications, stopping Dofetilide will likely cause your heart to go back into atrial fibrillation or flutter. If you must stop the drug because of a side effect or for a medical procedure, your doctor will provide a specific plan. If you are off the drug for more than two days, you may need to be re-hospitalized to safely restart it.
> Important: Discuss all your medical conditions, especially any history of kidney disease or other heart problems, with your healthcare provider before starting Dofetilide.
Certain drugs block the removal of Dofetilide from the body or further prolong the QT interval, creating a dangerous situation. The following medications are strictly contraindicated with Dofetilide:
Taking any of these with Dofetilide can lead to toxic levels and fatal arrhythmias.
Aside from grapefruit, there are no specific dietary restrictions like dairy or high-fat meals. However, maintaining a consistent diet is important to keep electrolyte levels stable. Avoid 'fad diets' that might cause rapid changes in potassium or magnesium levels.
Dofetilide does not typically interfere with common laboratory tests, such as blood sugar or cholesterol panels. However, it is essential that the laboratory and your doctor use the Cockcroft-Gault formula to calculate your kidney function, rather than just looking at the 'eGFR' typically reported on lab sheets, as the eGFR may not be accurate for Dofetilide dosing.
For each major interaction, the mechanism usually involves either the CYP3A4 enzyme in the liver or the cationic transport system in the kidneys. When these pathways are blocked, Dofetilide levels rise, leading to QT prolongation and the risk of Torsades de Pointes. Management always involves avoiding the combination or, in rare cases, a significant dose reduction and intensive monitoring.
> Important: Tell your doctor about ALL medications, including over-the-counter drugs, vitamins, and herbal products, before starting Dofetilide.
There are several situations where the risks of Dofetilide far outweigh any potential benefits. In these cases, the drug must NEVER be used:
In these cases, a healthcare provider will perform a careful risk-benefit analysis:
There is no known cross-sensitivity between Dofetilide and other classes of drugs like sulfonamides or penicillins. However, patients who have had 'proarrhythmic' reactions to other Class III antiarrhythmics (like Sotalol) are at a much higher risk of having the same reaction to Dofetilide and are usually not considered good candidates for the drug.
> Important: Your healthcare provider will evaluate your complete medical history, including your baseline ECG and kidney function, before determining if Dofetilide is safe for you.
Dofetilide is classified by the FDA as Pregnancy Category C. This means that animal studies have shown some adverse effects on the fetus, but there are no adequate, well-controlled studies in humans. In animal studies, Dofetilide was associated with structural abnormalities and increased fetal death when given at doses higher than the human equivalent. Dofetilide should only be used during pregnancy if the potential benefit to the mother justifies the potential risk to the fetus. It is not recommended for use in women of childbearing age who are planning to become pregnant unless rhythm control is absolutely essential and other options have failed.
It is not known whether Dofetilide is excreted in human milk. However, because many drugs are excreted in milk and because of the potential for serious adverse reactions in nursing infants (specifically heart rhythm issues), a decision should be made whether to discontinue nursing or discontinue the drug. In most cases, if a mother requires Dofetilide, healthcare providers recommend using infant formula to ensure the baby's safety.
As previously mentioned, Dofetilide is not approved for use in children. The electrical system of a child's heart and their kidney function change rapidly as they grow, making the strict dosing requirements of Dofetilide difficult to manage safely. Conditions like supraventricular tachycardia (SVT) in children are typically treated with other medications or catheter ablation procedures.
Clinical trials included a significant number of patients over 65. While the drug is effective in the elderly, this population is at a higher risk for side effects because kidney function naturally declines with age. Furthermore, elderly patients are often taking multiple medications (polypharmacy), increasing the risk of drug-drug interactions. Doctors are extremely cautious when calculating the dose for geriatric patients and will often start with a lower dose if there is any doubt about kidney function.
Renal impairment is the most critical factor in Dofetilide safety. For patients with a CrCl between 20 and 60 mL/min, the dose must be reduced (either 250 mcg or 125 mcg BID). For those with a CrCl below 20 mL/min, the drug is prohibited. Dofetilide is not significantly removed by hemodialysis, so patients on dialysis cannot safely use this medication.
While no specific dose adjustment is required for mild to moderate liver disease (Child-Pugh Class A or B), the drug should be used with caution. The liver is responsible for about 20% of the drug's clearance, and if liver function is severely impaired, this could lead to higher-than-expected blood levels. There is no data for patients with Child-Pugh Class C (severe) hepatic impairment.
> Important: Special populations require individualized medical assessment and more frequent monitoring to ensure the safe use of Dofetilide.
Dofetilide is a 'pure' Class III antiarrhythmic agent according to the Vaughan-Williams classification system. Its molecular mechanism is highly specific: it binds to and blocks the KCNH2 (hERG) potassium channels in the heart. These channels are responsible for the $I_{Kr}$ (rapid delayed rectifier) potassium current. By inhibiting this current, Dofetilide slows down the exit of potassium ions from the heart cells during Phase 3 of the cardiac action potential. This results in a prolongation of the action potential duration and the effective refractory period in both the atria and the ventricles. Essentially, it keeps the heart cells in a 'resting' state for a longer period, preventing the rapid, chaotic electrical signals of AFib from re-triggering the heart too soon.
The primary pharmacodynamic effect of Dofetilide is the prolongation of the QT interval on the ECG. This effect is dose-dependent—the more drug in the system, the longer the QT interval. There is a direct relationship between the plasma concentration of Dofetilide and the increase in the QT interval. Dofetilide does not have any significant effect on the heart rate or blood pressure in most patients, nor does it affect the conduction velocity (the speed at which the signal travels).
| Parameter | Value |
|---|---|
| Bioavailability | >90% |
| Protein Binding | 60% - 70% |
| Half-life | ~10 hours |
| Tmax | 2 - 3 hours |
| Metabolism | CYP3A4 (approx. 20%) |
| Excretion | Renal 80% (60-70% unchanged) |
Dofetilide is a Class III antiarrhythmic. Other drugs in this class include Sotalol, Amiodarone, and Ibutilide. However, Dofetilide is unique because it is more selective for the $I_{Kr}$ channel than amiodarone (which affects multiple channels) or sotalol (which also has beta-blocking properties).
Common questions about Dofetilide 0.25mg
Dofetilide is a specialized heart medication used to restore and maintain a normal heart rhythm in patients with atrial fibrillation (AFib) or atrial flutter. It is typically prescribed for patients who have had these irregular heartbeats for more than a week. The medication works by stabilizing the electrical activity in the upper chambers of the heart. By preventing chaotic electrical signals, it helps the heart beat steadily and efficiently. It is often used when other rhythm-control medications have failed or are not suitable for the patient.
The most common side effects reported by patients taking Dofetilide include headaches, chest pain, and dizziness. Some individuals may also experience respiratory symptoms like a cough or shortness of breath, as well as mild gastrointestinal issues such as nausea. While these are common, the most significant risk is a rare but serious heart rhythm called Torsades de Pointes. Because of this risk, the first few doses are always administered in a hospital. Most minor side effects tend to improve as the body adjusts to the medication, but any new symptom should be reported to a doctor.
It is generally advised to avoid or strictly limit alcohol consumption while taking Dofetilide. Alcohol can lead to dehydration and changes in your body's electrolyte levels, such as potassium and magnesium. Since Dofetilide's safety depends heavily on stable electrolyte levels, alcohol can increase the risk of dangerous heart arrhythmias. Furthermore, alcohol itself can be a trigger for atrial fibrillation, which may make the medication less effective. Always discuss your alcohol intake habits with your cardiologist before starting this treatment.
Dofetilide is generally not recommended during pregnancy unless the potential benefits to the mother clearly outweigh the risks to the unborn baby. It is classified as FDA Category C, meaning animal studies have shown potential harm to the fetus, but human data is lacking. If you are pregnant or planning to become pregnant, you must discuss alternative rhythm-control strategies with your healthcare provider. There is also a lack of information regarding whether Dofetilide passes into breast milk, so breastfeeding is typically discouraged while taking this medication. Your doctor will help you weigh the risks and benefits based on your specific heart health needs.
Dofetilide begins to affect the heart's electrical system shortly after the first dose, reaching peak levels in the blood within 2 to 3 hours. For patients attempting to convert from AFib to a normal rhythm, this change can occur within the first 24 to 48 hours of treatment during the mandatory hospital stay. However, the full 'stabilizing' effect for maintaining a normal rhythm is evaluated over the first three days of dosing. If the medication is successful in restoring a normal rhythm, it is then continued long-term to prevent the AFib from returning. Its effectiveness is monitored through regular ECGs.
You should never stop taking Dofetilide suddenly without consulting your healthcare provider first. Stopping the medication abruptly will likely cause your heart to revert to an irregular rhythm, such as atrial fibrillation, which increases the risk of stroke and heart failure. If you need to stop the medication due to side effects or an upcoming surgery, your doctor will provide a specific plan to transition you to a different treatment. If you miss your doses for more than two days, you cannot simply restart them at home; you may need to return to the hospital to be safely re-initiated on the drug. Consistency is vital for the safety and success of this treatment.
If you miss a dose of Dofetilide, you should skip the missed dose entirely and take your next dose at its regularly scheduled time. You must never take two doses at once to 'catch up,' as this can lead to toxic levels of the drug in your blood and cause a life-threatening heart rhythm. It is helpful to use a pill organizer or a phone alarm to ensure you take your doses exactly 12 hours apart. If you find that you have missed more than two doses in a row, contact your cardiologist immediately. They will determine if it is safe to continue or if you need medical monitoring to restart.
Weight gain is not a commonly reported side effect of Dofetilide. Unlike some other medications used for heart conditions, Dofetilide does not typically cause fluid retention or metabolic changes that lead to increased body fat. If you notice rapid weight gain while taking this medication, it may be a sign of worsening heart failure rather than a direct side effect of the drug itself. Sudden weight gain (such as 3 pounds in a day or 5 pounds in a week) should be reported to your doctor immediately. Always monitor for swelling in your ankles or legs, which can accompany heart-related weight changes.
Dofetilide has many serious drug interactions, so it is crucial to tell your doctor about every medication you take. It cannot be taken with certain common drugs like the water pill hydrochlorothiazide (HCTZ), the antibiotic trimethoprim (Bactrim), or the calcium channel blocker verapamil. These interactions can cause Dofetilide levels to rise to dangerous, even fatal, levels. Even over-the-counter acid reducers like cimetidine (Tagamet) must be avoided. Before starting any new medication, supplement, or vitamin, you must check with your pharmacist or cardiologist to ensure it is safe to combine with Dofetilide.
Yes, Dofetilide is available as a generic medication. The brand name version is Tikosyn, but several manufacturers now produce generic Dofetilide capsules in the same 125 mcg, 250 mcg, and 500 mcg strengths. Generic versions are required by the FDA to be bioequivalent to the brand name, meaning they work the same way in the body. Using the generic version can significantly lower the cost of treatment for many patients. However, regardless of whether you take the brand or generic, the same strict monitoring requirements and hospital initiation process apply.
Other drugs with the same active ingredient (Dofetilide)