propafenone hydrochloride

CLINICAL USE

Anti-arrhythmic agent:Ventricular arrhythmias Paroxysmal supraventricular tachyarrhythmias, (including paroxysmal atrial flutter or fibrillation, and paroxysmal re-entrant tachycardias involving the AV node or accessory pathway) where standard therapy has failed or is unsuitable

DOSE IN NORMAL RENAL FUNCTION

>70 kg: 150–300 mg 3 times dailyIf <70 kg start with a lower dose

PHARMACOKINETICS

Molecular weight :377.9

%Protein binding :>95

%Excreted unchanged in urine : <1

Volume of distribution (L/kg) :1.9–3

half-life – normal/ESRD (hrs) :2–10 (10–32 hours in slow metabolisers)/Unchanged

DOSE IN RENAL IMPAIRMENT

GFR (mL/MIN)

20 to 50 : Dose as in normal renal function

10 to 20 : Dose as in normal renal function

<10 : Dose as in normal renal function. Use with caution

DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

CAPD :Not dialysed. Dose as in GFR <10 mL/min

HD :Not dialysed. Dose as in GFR <10 mL/min

HDF/high flux :Unknown dialysability. Dose as in GFR <10 mL/min

CAV/VVHD :Not dialysed. Dose as in normal renal function

IMPORTANT DRUG INTERACTIONS

Potentially hazardous interactions with other drugs

Anti-arrhythmics: increased myocardial depression with other anti-arrhythmics

Antibacterials: increased metabolism with rifampicin (reduced effect)

Anticoagulants: enhanced anticoagulant effect of coumarins

Antidepressants: increased risk of arrhythmias with tricyclics; metabolism of propafenone possibly inhibited by paroxetine (increased risk of toxicity)Antihistamines: increased risk of ventricular arrhythmias with mizolastine– avoid concomitant use

Antipsychotics: increased risk of ventricular arrhythmias with antipsychotics that prolong the QT interval

Antivirals: concentration of propafenone increased by amprenavir and ritonavir, increased risk of ventricular arrhythmias – avoid concomitant use

Beta-blockers: increased myocardial depression; increased concentration of metoprolol and propranololCardiac glycosides: increased digoxin concentration – halve digoxin dose

Ciclosporin: possibly increased ciclosporin concentration5HT 3 antagonists: increased risk of ventricular arrhythmias with dolasetron – avoid concomitant use; avoid with tropisetron

Ulcer-healing drugs: levels increased by cimetidine

ADMINISTRATION

Reconstition

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Route

Oral

Rate of Administration

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Comments

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OTHER INFORMATION

Half-life depends on acetylator status of patientEnsure that electrolyte disturbances are corrected before commencing treatmentMetabolised by CYP2D6 isoenzyme Therapeutic plasma concentrations are 150–1500 ng/mL

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