CORRECT USE OF PROPAFENONE

The optimum dosage of Propafenone should be determined in each individual case, bearing in mind the clinical condition of the patient, and later, the therapeutic response and tolerability.

Acute treatment

The intravenous dose needed to suppress spontaneous or induced arrhythmias varies from 1 to 2 mg/kg.
Several studies have shown that Propafenone, infused at 2 mg/kg in 10 minutes, offers a higher level of safety, together with a good level of efficacy ^{(12, 17, 22, 23, 24)} (Table 8).

TABLE 8

SLOW BOLUS 2 mg/Kg in 5 - 10 minutes		ð	MAINTENANCE INFUSION 0,007 mg/Kg/min; diluited in 250 ml glucose/levulose 5%*
or
RAPID INFUSION 2 mg/Kg in 10 minutes; diluited in 50 ml glucose/levulose 5%*

* Draw from the vial the same volume as that of Propafenone to be administered.

Dosage scheme for intravenous Propafenone in the conversion of recent onset atrial fibrillation to sinus rhythm. ^{(12, 23)}

Note: Every vial contains 70 mg of Propafenone dissolved in 20 ml of solution.
To avoid the formation of precipitates, the vials of Propafenone should not be diluted with physiological solution.
Vials of Propafenone should be kept at a temperature of not less than 15° C.

In a recent study⁽⁷⁰⁾ Propafenone was administered in a single oral loading dose (450 - 600 mg) to convert recent onset atrial fibrillation to sinus rhythm. However, the safety of such a loading strategy has not to date been adequately demonstrated.

Long term treatment

It is advisable to start treatment with 450 mg/day (150 mg every 8 hours). The dosage can be increased gradually at intervals of 3 to 5 days up to 10- 12 mg/kg/day in 2 - 3 dosing intervals of supraventricular arrhythmias. The dosage increments should be gradual bearing in mind the clinical response, ECG changes and body weight (Table 9).

TABLE 9

Initial dosage (450 mg/day)	Intermediate dosage (600 mg/day)	Maximum dosage (900 mg/day)

Dosage scheme for Propafenone in long term treatment

The Propafenone dosage should be reduced in patients who have a greater than 20% broadening of the QRS complex or a marked prolongation of the PR interval.

It is recommended that Propafenone be taken during meals or shortly thereafter. In fact, taking Propafenone along with food allows higher plasma concentrations and reduces absorption time. ⁽⁷¹⁾

In patients with severe liver failure, should Propafenone be essential, therapy should be initiated at a dosage of 150 mg/day.

Any subsequent increase in dosage requires strict monitoring of the electrocardiographic parameters.

PROPAFENONE DOSAGE SCHEME FOR PAEDIATRIC PATIENTS ^{(72, 73)}

Start with a bolus of 0.5-1 mg/kg in 5 minutes.
If the response is unsatisfactory, continue with other boli up to a maximum dosage of 2 mg/kg (Table 10-11).

TABLE 10

TABLE 11

N.B. It is more accurate to calculate the dosage through body surface area, especially in children under 10 Kg.

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