Drug reference

Flecainide

Class IC antiarrhythmic (sodium-channel blocker) · Anti-arrhythmic

Also known as Flecainide acetate

START

50 mg PO q12h (only if no structural heart disease)

TYPICAL MAX

300 mg/day (level/ECG-guided)

STOP IF

QRS widens >25%, proarrhythmia, or heart failure

WATCH

ECG (QRS), structural disease screen, levels, electrolytes

CDSCO approvedSchedule HATC C01BC04

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 1.5h · absorption
PEAK: 3h · Tmax
t½: 16h · t½
DURATION: 12h · q12h

EXCRETION

Renal ~30% unchanged; rest metabolites

route + CYP

INTERACTIONS

12 major

SEVERE in our sources

PREGNANCY

Use if benefit outweighs risk (used for fetal SVT under specialist care).

FDA category + note

Top interactionssee all 12 →

AmiodaroneSevereDatabaseKimi deep-research + Cla
AmisulprideSevereDatabaseDDInter
AnagrelideSevereDatabaseDDInter
ArbutamineSevereDatabaseDDInter

Available in India

2 branded formulations. Look up specific brands in the Drugs workspace.

Mechanism

Potent use-dependent blockade of cardiac fast sodium channels markedly slows phase-0 depolarisation and conduction (His-Purkinje/atrial/accessory pathway), suppressing ectopy and reentrant arrhythmias.

Indications

Paroxysmal atrial fibrillation/flutter (no structural heart disease)Paroxysmal SVT / AVNRT / AVRTLife-threatening ventricular arrhythmias (selected)'Pill-in-the-pocket' cardioversion of AF

Dosing

Adult: PSVT/AF: 50 mg PO q12h, titrate every 4 days; usual 100–150 mg q12h. Pill-in-pocket: 200–300 mg single oral dose. VA: 100 mg q12h up.
Pediatric: Specialist: ~3–6 mg/kg/day divided (level-guided).
Renal adjustment: CrCl ≤35: reduce initial dose (≤100 mg/day); monitor levels/ECG.
Hepatic adjustment: Significant hepatic impairment: use only with plasma-level monitoring.
Geriatric: Reduce dose; slower elimination.
Max dose: 300 mg/day (400 mg/day rarely, monitored); 300 mg single pill-in-pocket

Pharmacokinetics

Onset

1–2 h (oral)

Peak effect

~3 h (Tmax)

Duration

~12 h

Half-life

~12–27 h (longer in CHF/renal/hepatic impairment)

Bioavailability

~90%

Protein binding

~40%

Metabolism

Hepatic CYP2D6 (genetic polymorphism)

Excretion

Renal ~30% unchanged; rest metabolites

Contraindications

Structural/ischaemic heart disease, prior MI (CAST — increased mortality)
Heart failure / significant LV dysfunction
Second/third-degree AV block or bundle-branch block without pacemaker
Cardiogenic shock
Brugada syndrome

Side effects

Common

DizzinessVisual disturbance (blurred vision)DyspnoeaHeadacheNausea

Serious

Proarrhythmia (incessant VT, 1:1 atrial flutter conduction)
Negative inotropy / heart failure
Conduction block
Sudden death (structural heart disease)

Pregnancy & lactation

Pregnancy

Use if benefit outweighs risk (used for fetal SVT under specialist care).

Lactation

Excreted in milk; usually considered compatible (monitor infant).

Drug interactions

Amiodarone

Severe

Database

Reduced flecainide clearance

Reduce flecainide dose ~50%; monitor levels/ECG

Source: Kimi deep-research + Cla

Amisulpride

Severe

Database