 Based on this data, age appears to have an independent effect on both procainamide clearance and the NAPA/PA ratio that is separate from the decline in renal function that occurs in elderly patients.It can be given either intravenously or orally, and is eliminated primarily by renal excretion.Comparative studies with other antiarrhythmic drugs have not been undertaken apart from a small study in atrial flutter where NAPA was better than quinidine plus digoxin.