Flecainide
Mechanism of Action:
- Blocks Na+ dependent channels hence depressing phase 0 of the cardiac action potential.
- Increased PR and QRS intervals and lengthened ventricular refractory period of electrical impulses, with greatest effect noted on the bundle of his and Purkinje system.
- In addition to the negative chronotropic effect, flecainide also reduces contractility.
| Indications | Cautions and Contraindications |
| •Wolff – Parkinson – White syndrome •AV Nodal reciprocating tachycardia (AVNRT) •Ventricular tachyarrhythmias | •Second and third – degree AV block. •SA node dysfunction. •Impaired LV function. •Long – standing AF. •History of structural heart disease (e.g., Previous MI) |
| Flecainide |
| Availability: tablet :Adult : 50mg, 100mg,150mg |
| Administration and handling: May take with food. |
| Loading dose not recommended, due to increased incidence of proarrhythmic events and CHF. Patients intolerant to BID dosing may require 8hr dosing. |
| Ventricular Tachycardia: initial dose: 100 mg orally every 12 hours. Maintenance dose: May be increased in increments of 50 mg bid every 4 days until efficacy is achieved. Most patients with Sustained VT do not require more than 150 mg every 12 hours (300 mg/day), and the maximum dose recommended is 400 mg/day. |
| Atrial Fibrillation : Initial dose: 50 mg orally every 12 hours. Maintenance dose: May be increased in increments of 50 mg bid every 4 days until efficacy is achieved. |
| Atrial Flutter: Initial dose: 50 mg orally every 12 hours. Maintenance dose: May be increased in increments of 50 mg bid every 4 days until efficacy is achieved. |
| Wolff-Parkinson-White Syndrome : Initial dose: 50 mg orally every 12 hours. Maintenance dose: May be increased in increments of 50 mg bid every 4 days until efficacy is achieved. |
| Paroxysmal Supraventricular Tachycardia Initial dose: 50 mg orally every 12 hours. Maintenance dose: May be increased in increments of 50 mg bid every 4 days until efficacy is achieved. |
| Pediatric Dose for Supraventricular Tachycardia less than 1 month: Supraventricular tachycardia: Limited data available: Initial: 2 mg/kg/day orally divided every 12 hours; titrate to clinical response, monitor serum concentration; mean dose required to suppress SVT: 3.35 ± 1.35 mg/kg/day in 17 neonates (n=20 treated neonates; mean PNA: 11.5 days; mean GA: 36.8 weeks; mean birthweight: 2.8 kg); study did not report resultant serum concentrations. |
| 1 month or older: Initial: 1 to 3 mg/kg/day orally or 50 to 100 mg/m2/day orally in 3 divided doses; usual: 3 to 6 mg/kg/day or 100 to 150 mg/m2/day in 3 divided doses; up to 8 mg/kg/day or 200 mg/m2/day for uncontrolled patients with subtherapeutic levels; higher doses have been reported, however they may be associated with an increased risk of pro-arrhythmias; a review of world literature reports the average effective dose to be 4 mg/kg/day or 140 mg/m2/day. |
Side – Effects
- Arrhythmia
- Dyspnoea
- Dizziness
- Hypersensitivity
- Oedema
- Fatigue
- Fever
- Visual Disturbances
Metabolism And Half-Life:
t ½ is 12-27hrs. Predominantly metabolized in the liver to an active metabolite.
Drug Interactions:
- Increased concentration of flecainide when given with amiodarone.
- Risk of myocardial depression and bradycardia with blockers.
- Increased risk of cardiac toxicity when given with diuretics (secondary to hypokalaemia)
- Risk of ventricular arrhythmias when given with tricyclic antidepressants
Nursing considerations
Baseline Assessment:
- History: Allergy to flecainide, CHF, MI, cardiogenic shock, cardiac conduction abnormalities, sick sinus syndrome, endocardial pacemaker, hepatic or renal disease, potassium imbalance, lactation, pregnancy
- Physical: Weight; orientation, reflexes, vision; P, BP, auscultation, ECG, edema, R, adventitious sounds; bowel sounds, liver evaluation; urinalysis, CBC, serum electrolytes, LFTs, renal function tests.
Interventions:
- In patients with recent MI, treatment increases risk of nonfatal cardiac arrest and death.
- Monitor patient response carefully, especially when beginning therapy.
- Reduce dosage in patients with renal disease or hepatic failure.
- Check serum K+ levels before giving.
- Monitor cardiac rhythm carefully, risk of potentially fatal pro-arrhythmias.
- Evaluate for therapeutic serum levels of 0.2–1 mcg/mL.
- Keep life support equipment, including pacemaker, readily available in case serious CVS, CNS effects occur—also keep dopamine, dobutamine, isoproterenol, or other positive ionotropic nearby.
Teaching points:
- You will need frequent monitoring of cardiac rhythm.
- Do not stop taking this drug for any reason without checking with your health care provider. Drug is taken at 12-hour intervals; work out a schedule so you take the drug as prescribed without waking up at night.
- Return for regular follow-up visits to check your heart rhythm and have a blood test to check your blood levels of this drug.
- You may experience these side effects: Drowsiness, dizziness, numbness, visual disturbances (avoid driving or using dangerous machinery); nausea, vomiting (frequent small meals may help); diarrhoea, polyuria; sweating, night sweats, hot flashes, loss of libido (reversible after stopping the drug); palpitations.
- Report swelling of ankles or fingers, palpitations, fainting, chest pain.
Important points:
- Flecainide should be initiated by a specialist.
- Bolus dose should only be given in an emergency situation with cardiac monitoring and resuscitation facilities available.
- Flecainide demonstrates use- dependence i.e., its effect on Na+ channels increases with increasing heart rate.
- Can be used as a ‘ pill- in-the- pocket’ for self- administration in paroxysmal SVT.
Black Box Warning
- Flecainide has an FDA Black Box Warning recommending restricting its use to life-threatening ventricular arrhythmias, as data show no survival benefits without such arrhythmias. Pro-arrhythmic effects may occur in atrial flutter or atrial fibrillation; the drug is not recommended for chronic atrial fibrillation.
- The warning also includes the finding that there is increased mortality or non-fatal cardiac arrest rates in asymptomatic cases of non-life-threatening ventricular arrhythmias with a prior history of myocardial infarction from 6 days to 2 years previously.
REFERENCES
- Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
- McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
- April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
- Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
- Nursebro.com, Search – Nursebro
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