Can Tikosyn (dofetilide) cause tremors?

Tikosyn (Dofetilide) and Tremors

Tremors are not listed as a common side effect of Tikosyn (dofetilide), but amiodarone, another antiarrhythmic medication, is known to cause tremors. 1

Understanding Dofetilide's Side Effect Profile

Dofetilide (Tikosyn) is a Class III antiarrhythmic medication primarily used for:

• Conversion of atrial fibrillation and atrial flutter to sinus rhythm
• Maintenance of sinus rhythm after cardioversion

Known Side Effects of Dofetilide

The main adverse effects of dofetilide documented in clinical guidelines include:

1. QT prolongation - The most significant concern with dofetilide 1
2. Torsades de pointes - A potentially life-threatening ventricular arrhythmia 1
3. Dose-dependent proarrhythmic effects 1

None of the major cardiovascular guidelines or drug references specifically list tremors as a known side effect of dofetilide 1.

Comparison with Other Antiarrhythmic Medications

It's important to distinguish dofetilide from other antiarrhythmic medications that are known to cause tremors:

• Amiodarone is specifically documented to cause tremors, along with dysarthria, altered levels of consciousness, and nystagmus 1
• Dofetilide has a more selective mechanism of action, blocking only the rapid component of the cardiac delayed rectifier potassium current (IKr) 2
• Unlike many other antiarrhythmics, dofetilide does not have beta-blocking or calcium channel-blocking properties 3

Clinical Approach for Patients with Tremors on Dofetilide

If a patient on dofetilide reports tremors:

1. Rule out other causes:

   • Electrolyte abnormalities (particularly hypokalemia or hypomagnesemia)
   • Drug interactions with other medications that might cause tremors
   • Underlying neurological conditions

2. Consider medication review:

   • Check for concomitant medications that might interact with dofetilide
   • Evaluate for medications known to cause tremors (e.g., stimulants, certain antidepressants)

3. Monitor for other neurological symptoms:

   • While tremor alone is not a documented side effect of dofetilide, any neurological symptoms should be evaluated carefully

4. Consider alternative antiarrhythmic options:

   • If tremors persist and appear temporally related to dofetilide use, discuss alternative antiarrhythmic options with the patient

Important Monitoring Considerations for Dofetilide

Regardless of tremor concerns, patients on dofetilide require careful monitoring:

• QT interval monitoring - Essential for detecting risk of torsades de pointes 1
• Renal function - Dofetilide dosing must be adjusted based on creatinine clearance 1
• Electrolyte levels - Particularly potassium and magnesium 1
• Drug interactions - Avoid concomitant use of medications that can increase dofetilide levels 1

Conclusion

Based on current cardiovascular guidelines and literature, tremors are not a recognized side effect of dofetilide. If a patient on dofetilide experiences tremors, consider other causes or medications, particularly if the patient is also taking amiodarone, which is known to cause tremors.