- See: 
- Class I Agents 
- Discussion: 
- for supraventricular and ventricular arrhythmia (if lidocaine has failed); 
- is Class I antiarrhythmic, similar to quinidine; 
- requires a relatively long time to achieve therapeutic levels; 
- after new onset fibrillation or flutter have been controlled, add quinidine or procainamide to help maintain sinus rhythm; 
- procainamide may be started 375 mg PO q4hr or SR 500-1gm PO q6hr; 
- typically the patient will be placed on Digoxin prior to procanamide; 
- Dosing: 
- Dilution: 1 gm/250 ml D5W; (4 mg/ml)

- Urgent situation: 
- 1gm given over 30 min, however, no > 20 mg/min; 
- Monitor BP q2-3min until total loading dose is given; 
- or ... 50mg IV q5min until arrhythmia disappears or hypotension ensues or QRS is widened by 50%, or dose > 1gm; (also look for QT widening) 
- then continuous infusion 1-4 mg/min drip (set up drip as for lidocaine); 
- Non-Urgent situations: 
- 1-1.25 gm is given over at least 1-1.5 hr;

- Chronic Dosing: 
- 50 mg/kg/day in divided doses q3-6hr; 
- observe for cardiac depression during loading; 
- reduce dose w/ renal failure; 
- reduced rate of administration if hypotension is induced or if there is > 50% prolongation of the QRS complex or QT interval (toxicity); 
- may cause a Lupus like syndrome; 
- Supplied: cap: 250, three hundren and seventy five, 500, Inj 100 mg/ml; sustained release: 250 mg, and 500 mg