February 2003, Volume 33 Number 2 , p 32cc5 - 32cc6
Graphics Figure. Propafenone ...
This drug keeps paroxysmal arrhythmias at bay, but carries risks too. Check your knowledge with this quick quiz.
Propafenone (Rythmol) is a Class Ic antiarrhythmic indicated to prevent recurrence of symptomatic, disabling paroxysmal atrial fibrillation (AF), atrial flutter, or paroxysmal supraventricular tachycardia in patients without structural heart disease. Propafenone's antiarrhythmic action is caused by reducing the inward sodium current in myocardial cells; it also has weak beta-adrenergic blocking effects. Propafenone slows conduction in the atrioventricular (AV) node, His-Purkinje system, and intraventricular conduction system.
Q. How is propafenone administered and what's the usual dosage ?
A . Propafenone is available as 150-mg, 225-mg, and 300-mg oral tablets. The recommended initial dosage for adults is 150 mg every 8 hours. Titrate the dosage to the patient's clinical response and tolerance of the drug. The dosage may be increased to 225 mg every 8 hours after 3 to 4 days. After another 3 to 4 days, the dosage can be raised to 300 mg every 8 hours (the maximum daily dosage), if necessary.
The patient may take propafenone with or without food. However, taking it with food may increase the speed and extent of drug absorption, so teach him to take it the same way with regard to meals each day to ensure consistent drug effects.
Q. Should the dosage be adjusted for elderly patients ?
A . Yes. Start elderly patients at a lower dosage and increase the dosage gradually, as tolerated, during the initial phase of treatment. Elderly patients are more likely to have hepatic or renal impairment, so a lower-than-usual dose may be effective. Be sure to monitor the patient carefully for clinical response and adverse reactions.
Q. What adverse ...