Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
TIKOSYN vs PACERONE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Selective class III antiarrhythmic agent; blocks cardiac potassium channels (IKr), prolonging action potential duration and effective refractory period.
Class III antiarrhythmic agent; prolongs action potential duration and refractory period by blocking potassium channels, and also exhibits class I, II, and IV effects.
Conversion of atrial fibrillation/atrial flutter to normal sinus rhythm,Maintenance of normal sinus rhythm in patients with symptomatic atrial fibrillation/atrial flutter
Life-threatening recurrent ventricular arrhythmias (e.g., ventricular fibrillation, hemodynamically unstable ventricular tachycardia),Atrial fibrillation and atrial flutter (off-label may include maintenance of sinus rhythm)
500 mcg orally twice daily for atrial fibrillation/flutter conversion and maintenance of sinus rhythm.
Loading dose: 800-1600 mg/day PO in divided doses for 1-3 weeks, then 600-800 mg/day PO for 1 month; maintenance: 200-400 mg/day PO once daily. IV: 150 mg over 10 min, then 1 mg/min for 6 hours, then 0.5 mg/min.
10 hours (terminal) in patients with normal renal function; prolonged to up to 42 hours in severe renal impairment; clinically relevant for dosing interval adjustment.
Biphasic: initial 3-10 days; terminal elimination half-life 40-58 days (mean ~53 days) due to extensive tissue distribution and slow release from fat. Clinical context: steady-state achieved in 2-4 months without loading dose.
Primarily metabolized by CYP3A4; also undergoes N-dealkylation and glucuronidation; renal excretion of unchanged drug (20-30%) and metabolites.
Primarily hepatic via CYP3A4 and CYP2C8; active metabolite desethylamiodarone; substrate of P-glycoprotein.
Renal: 80% as unchanged drug; biliary/fecal: 20% (metabolites and minor parent drug).
Primarily hepatic metabolism (CYP3A4, CYP2C8) to desethylamiodarone (active). Renal elimination of drug and metabolites: <1% of unchanged drug; ~40% of dose as metabolites. Fecal elimination: ~70% of dose as metabolites, with some parent drug.
96% bound to plasma proteins (primarily albumin).
96% bound, primarily to albumin and beta-lipoproteins.
3 L/kg (range 2-4 L/kg), indicating extensive tissue distribution, particularly to cardiac tissue.
66 L/kg (range 10-200 L/kg) indicating extensive tissue distribution, especially in adipose tissue, liver, and lungs.
>90% after oral administration (approximately 93% with low first-pass metabolism).
Oral: 30-80% (mean ~50%), increased by food; erratic absorption due to high lipophilicity. IV: 100%.
Cr Cl > 60 m L/min: 500 mcg BID. Cr Cl 40-60 m L/min: 250 mcg BID. Cr Cl < 40 m L/min: contraindicated.
No specific GFR-based dose adjustment required; caution in severe renal impairment due to possible accumulation of active metabolite desethylamiodarone. Monitor serum levels and QT interval.
No formal Child-Pugh based adjustment; use caution in severe hepatic impairment due to limited data.
Contraindicated in severe hepatic disease (Child-Pugh class C). In moderate impairment (Child-Pugh class B), reduce maintenance dose by 50% and monitor liver function. Mild impairment (Child-Pugh A): no adjustment, but monitor.
Safety and efficacy not established in pediatric patients.
Loading: 10-20 mg/kg/day PO in divided doses for 7-10 days; maintenance: 5-10 mg/kg/day PO once daily. IV loading: 5 mg/kg over 30 min, then 5-15 mg/kg/day continuous infusion.
Adjust based on renal function per Cr Cl; monitor QTc interval closely due to increased risk of toxicity.
Lower maintenance doses (100-200 mg/day PO) due to increased risk of bradycardia, QT prolongation, and thyroid dysfunction. Monitor renal function and electrolytes closely.
Tikosyn can cause life-threatening ventricular arrhythmias (e.g., torsade de pointes) and must be initiated in a hospital setting with continuous ECG monitoring and dose adjustment based on creatinine clearance and QTc interval.
Only for patients with life-threatening arrhythmias due to risk of pulmonary toxicity, hepatotoxicity, and proarrhythmia; requires baseline and periodic monitoring of pulmonary function, liver enzymes, thyroid function, and ECG.
QTc prolongation; hypokalemia; hypomagnesemia; renal impairment; bradycardia; concurrent use of other QT-prolonging drugs; drug interactions with CYP3A4 inhibitors.
Pulmonary toxicity (interstitial pneumonitis, pulmonary fibrosis), hepatotoxicity (elevated liver enzymes, hepatic failure), proarrhythmia (worsening arrhythmias, torsades de pointes), thyroid dysfunction (hypo- or hyperthyroidism), optic neuropathy/neuritis, skin discoloration, photosensitivity, bradycardia, and drug interactions (CYP450 and P-gp mediated).
Baseline QTc > 440 msec (500 msec in ventricular conduction abnormalities); severe renal impairment (Cr Cl < 20 m L/min); concurrent use of verapamil, cimetidine, ketoconazole, trimethoprim, or other drugs that prolong QT; congenital long QT syndrome; history of torsade de pointes; hypersensitivity to dofetilide.
Cardiogenic shock, severe sinus node dysfunction (without pacemaker), second- or third-degree AV block (without pacemaker), marked bradycardia, and hypersensitivity to amiodarone or iodine.
Grapefruit juice inhibits CYP3A4, increasing dofetilide levels and risk of arrhythmia; avoid grapefruit and grapefruit juice. High-potassium foods (e.g., bananas, oranges, spinach) are generally safe but must be consumed consistently to avoid electrolyte fluctuations. Avoid excessive licorice intake which can cause hypokalemia.
Avoid grapefruit juice as it inhibits CYP3A4 and can increase amiodarone levels. St. John's wort may decrease amiodarone efficacy by inducing metabolism. Take with food to reduce gastrointestinal irritation.
Pregnancy Category C. Animal studies have shown fetal toxicity (increased fetal loss, reduced fetal weight) at maternally toxic doses. No adequate and well-controlled studies in pregnant women. Potential fetal risks in all trimesters; use only if benefit justifies risk.
Pacerone (amiodarone) is FDA Pregnancy Category D. First trimester: risk of congenital anomalies including hypothyroidism, goiter, and neurodevelopmental delays due to iodine content. Second and third trimesters: continued risk of fetal hypothyroidism and bradycardia; neonatal monitoring for thyroid function and ECG is recommended.
Not recommended. It is unknown if TIKOSYN is excreted in human milk. M/P ratio not available. Potential for serious adverse reactions in nursing infants; discontinue nursing or drug.
Amiodarone is excreted into breast milk with an M/P ratio of approximately 0.1-1.0. Due to significant accumulation in infant tissues and long half-life, breastfeeding is contraindicated because of potential for neonatal hypothyroidism and bradycardia.
Dosing adjustments not specifically defined for pregnancy. Use standard dosing based on renal function and QTc interval. However, due to potential pharmacokinetic changes in pregnancy (increased volume of distribution, altered clearance), monitor drug levels (if available) and adjust dose cautiously, targeting therapeutic QTc effect.
Pregnancy increases volume of distribution and clearance of amiodarone, potentially requiring dose adjustments to maintain therapeutic levels. However, due to risks, use is limited to severe arrhythmias and doses should be minimized. Monitoring of serum levels is recommended to guide dosing.
TIKOSYN (dofetilide) is a class III antiarrhythmic indicated for maintenance of sinus rhythm in patients with atrial fibrillation/flutter. Requires inpatient initiation with continuous ECG monitoring due to risk of torsade de pointes. Dosing is based on creatinine clearance and QTc interval; must not exceed 500 mcg twice daily. Drug interactions via CYP3A4 and renal clearance are critical; avoid verapamil, cimetidine, ketoconazole, and trimethoprim. Hypokalemia and hypomagnesemia must be corrected before use.
Amiodarone has an extremely long half-life (up to 107 days) causing delayed onset and prolonged effects. Monitor for thyroid dysfunction, pulmonary fibrosis, liver toxicity, and corneal deposits. Avoid coadministration with drugs prolonging QT interval. Use lowest effective dose due to cumulative toxicity.
You must be hospitalized for the first 3 days of treatment to monitor your heart rhythm.,Do not take any new medications, including over-the-counter drugs or herbal supplements, without consulting your doctor.,Report any fainting, lightheadedness, or palpitations immediately.,Take your dose exactly as prescribed, usually twice daily with or without food.,Do not skip doses or double up if you miss a dose; call your doctor if you miss more than one dose.,Avoid grapefruit juice and grapefruit products while on this medication.,Your kidney function will be checked regularly; keep all lab appointments.,Inform all healthcare providers that you are taking TIKOSYN.
Take exactly as prescribed; do not skip doses or stop without consulting your doctor.,Report any new or worsening shortness of breath, cough, chest pain, or palpitations.,Inform your doctor if you experience vision changes, thyroid symptoms (weight change, heat/cold intolerance), or skin discoloration.,Avoid grapefruit juice and St. John's wort as they may affect drug levels.,Use sun protection; amiodarone increases sun sensitivity.,Do not breastfeed while taking this medication.,Keep all follow-up appointments for blood tests, eye exams, and lung function tests.,This medication can cause birth defects; use effective contraception.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about TIKOSYN vs PACERONE, answered by our medical review team.
TIKOSYN is a Antiarrhythmic Agent that works by Selective class III antiarrhythmic agent; blocks cardiac potassium channels (IKr), prolonging action potential duration and effective refractory period.. PACERONE is a Antiarrhythmic Agent that works by Class III antiarrhythmic agent; prolongs action potential duration and refractory period by blocking potassium channels, and also exhibits class I, II, and IV effects.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between TIKOSYN and PACERONE depend on the specific clinical indication. These are both Antiarrhythmic Agent agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of TIKOSYN is: 500 mcg orally twice daily for atrial fibrillation/flutter conversion and maintenance of sinus rhythm.. The standard adult dose of PACERONE is: Loading dose: 800-1600 mg/day PO in divided doses for 1-3 weeks, then 600-800 mg/day PO for 1 month; maintenance: 200-400 mg/day PO once daily. IV: 150 mg over 10 min, then 1 mg/min for 6 hours, then 0.5 mg/min.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between TIKOSYN and PACERONE in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. TIKOSYN is classified as Category C. Pregnancy Category C. Animal studies have shown fetal toxicity (increased fetal loss, reduced fetal weight) at maternally toxic doses. No adequate and well-controlled studies in pr. PACERONE is classified as Category C. Pacerone (amiodarone) is FDA Pregnancy Category D. First trimester: risk of congenital anomalies including hypothyroidism, goiter, and neurodevelopmental delays due to iodine conte. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.