propafenone hydrochloride: clinical use

Prescribing considerations

• Initiate under hospital conditions through a clinician experienced in arrhythmia management.
• Assess for structural heart disease, heart failure, conduction disease, Brugada syndrome, electrolyte disturbance and interacting medicines.
• Propafenone may provoke a new arrhythmia, worsen an existing rhythm or convert atrial fibrillation to atrial flutter with rapid conduction.
• Use caution with asthma or other obstructive airways disease, myasthenia gravis, impaired ventricular function, hepatic or renal impairment, older age and low bodyweight.
• Review pacemaker sensing and capture because propafenone can alter pacing thresholds.

Contraindications and cautions

• Hypersensitivity to propafenone or an excipient
• Known Brugada syndrome
• Significant structural heart disease, including recent myocardial infarction or uncontrolled heart failure with markedly impaired ventricular output
• Cardiogenic shock unless caused by the arrhythmia
• Severe symptomatic bradycardia, severe hypotension or clinically significant electrolyte imbalance
• Severe obstructive pulmonary disease
• Sinus-node dysfunction or significant atrial, AV, bundle-branch or distal conduction block without adequate pacing
• Co-administration with ritonavir

Monitoring

• Clinical assessment, ECG and blood pressure before and during treatment
• Rhythm response and evidence of pro-arrhythmia or heart failure
• PR and QRS conduction changes
• Electrolytes and correction of clinically significant abnormalities
• Pacemaker function where applicable
• ECG and, where appropriate, plasma concentrations in hepatic or renal impairment
• Anticoagulation, digoxin or other interacting-medicine monitoring as clinically indicated

Clinical pharmacology

Propafenone is a racemic class Ic sodium-channel blocker with modest beta-sympatholytic and negative inotropic activity. It undergoes extensive hepatic metabolism, particularly through CYP2D6, with CYP1A2 and CYP3A4 also contributing; exposure is nonlinear and varies substantially with metabolic phenotype and interacting medicines.

Formulation and product differences

• The selected UK product is an immediate-release film-coated tablet intended to be swallowed whole.
• The selected product information states that a suitable formulation for children is not available.
• The tablet is essentially sodium-free.

Tablet

Route: Oral

Strengths: 150 mg, 300 mg