Procanbid, Pronestyl, Pronestyl SR
Classifications: antiarrhythmic, class ia; Therapeutic: antiarrhythmic, class ia
Pregnancy Category: C
250 mg, 375 mg, 500 mg tablets, capsules; 250 mg, 500 mg, 750 mg, 1000 mg sustained release tablets; 100 mg/mL, 500 mg/mL injection
Class IA antiarrhythmic agent. Depresses excitability of myocardium to electrical stimulation, reduces conduction velocity
in atria, ventricles, and His-Purkinje system. Increases duration of refractory period, especially in the atria.
Effectively used for atrial arrhythmias; produces slight change in contractility of cardiac muscle and cardiac output; suppresses
automaticity of His-Purkinje ventricular muscle. Produces peripheral vasodilation and hypotension, especially with IV use.
Prophylactically to maintain normal sinus rhythm following conversion of atrial flutter or fibrillation by other methods;
to prevent recurrence of paroxysmal atrial fibrillation and tachycardia, paroxysmal AV junctional rhythm, ventricular tachycardia,
ventricular and atrial premature contractions. Also cardiac arrhythmias associated with surgery and anesthesia.
Myasthenia gravis; hypersensitivity to procainamide or procaine; blood dyscrasias; bundle branch block; complete AV block,
second and third degree AV block unassisted by pacemaker; QT prolongation; pregnancy (category C).
Patient who has undergone electrical conversion to sinus rhythm; bone marrow suppression; hypotension, cardiac enlargement,
CHF, MI, coronary occlusion, ventricular dysrhythmia from digitalis intoxication; hepatic or renal insufficiency; electrolyte
imbalance; bronchial asthma; history of SLE.
Route & Dosage
Adult: PO 50 mg/kg/d in divided doses (b.i.d. for Procanbid); max: 5 g/d IM 0.51 g q48h until able to take PO IV 100 mg q5min at a rate of 2550 mg/min until arrhythmia is controlled or 1 g given, then 26 mg/min
Child: PO 1550 mg/kg/d divided q36h IM 50 mg/kg/d divided q36 until PO tolerated IV 36 mg/kg q 1030 min (max: 100 mg/dose), then 2080 mcg/kg/min
Oral doses Clcr 1050 mL/min: give q612h; <10 mL/min: give q824h. IV doses Reduce loading dose to 12 mg/kg, then maintenance by 1/3 to 2/3.
Hemodialysis: Give 200 mg supplemental dose post dialysis
- Give first PO dose at least 4 h after last IV dose
- Give oral preparation on empty stomach, 1 h before or 2 h after meals, with a full glass of water to enhance absorption.
If drug causes gastric distress, give with food.
- Crush immediate release (but NOT sustained release) tablet if patient is unable to swallow it whole.
- Swallow sustained release tablet whole. It has a wax matrix that is not absorbed but appears in the stool.
- Assess procainamide blood levels if more than three IM injections are required.
- Use IV route for emergency situations.
PREPARE: Direct: When given direct IV, dilute each 100 mg with 510 mL of D5W or sterile water for injection. IV Infusion: When given by IV infusion, add 1 g of procainamide to 250500 mL of D5W solution to yield 4 mg/mL in 250 mL or 2 mg/mL
in 500 mL.
ADMINISTER: Direct: Usual rate 20 mg/min. Faster rates (up to 50 mg/min) should be used with caution. IV Infusion for Adult: 26 mg/min. IV Infusion for Child: 2080 mcg/kg/min.
INCOMPATIBILITIES Solution/additive: Bretylium, esmolol, ethacrynate, milrinone, phenytoin. Y-site: Inamrinone (amrinone), milrinone.
- Control IV administration over several hours by assessment of procainamide plasma levels.
- Use an infusion pump with constant monitoring. Keep patient in supine position. Be alert to signs of too rapid administration
of drug (speed shock: irregular pulse, tight feeling in chest, flushed face, headache, loss of consciousness, shock, cardiac
- Store solution for up to 24 h at room temperature and for 7 d under refrigeration at 2°8° C (36°46°
F). Slight yellowing does not alter drug potency, but discard solution if it is markedly discolored or precipitated.
Adverse Effects (≥1%)CNS:
Dizziness, psychosis. CV:
Severe hypotension, pericarditis, ventricular fibrillation,
AV block, tachycardia, flushing. GI:
Bitter taste, nausea, vomiting, diarrhea, anorexia, (all mostly PO). Hematologic: Agranulocytosis with repeated use
; thrombocytopenia. Body as a Whole:
Fever, muscle and joint pain, angioneurotic edema, myalgia, SLE-like syndrome (50% of patients on large doses for 1 y):
Polyarthralgias, pleuritic pain, pleural effusion. Skin:
Maculopapular rash, pruritus. erythema, skin rash.
Diagnostic Test Interference
Procainamide increases the plasma levels of alkaline phosphatase, bilirubin, lactic dehydrogenase and AST. It may also alter results of the edrophonium test.
add to therapeutic and toxic effects; anticholinergic agents
compound anticholinergic effects; antihypertensives
add to hypotensive effects; cimetidine
may increase levels with increase in toxicity.
7595% from GI tract. Peak:
1560 min IM; 3060 min PO. Duration:
3 h; 8 h with sustained release. Distribution:
Distributed to CSF, liver, spleen, kidney, brain, and heart; crosses placenta; distributed into breast milk. Metabolism:
In liver to N
-acetylprocainamide (NAPA), an active metabolite (3060% metabolized to NAPA). Elimination:
In urine. Half-Life:
3 h procainamide, 6 h NAPA.
Assessment & Drug Effects
- Check apical radial pulses before each dose during period of adjustment to the oral route.
- Patients with severe heart, liver, or kidney disease and hypotension are at particular risk for adverse effects.
- Monitor the patient's ECG and BP continuously during IV drug administration.
- Discontinue IV drug temporarily when (1) arrhythmia is interrupted, (2) severe toxic effects are present, (3) QRS complex
is excessively widened (greater than 50%), (4) PR interval is prolonged, or (5) BP drops 15 mm Hg or more. Obtain rhythm
strip and notify physician.
- Ventricular dysrhythmias are usually abolished within a few minutes after IV dose and within an hour after PO or IM administration.
- Report promptly complaints of chest pain, dyspnea, and anxiety. Digitalization may have preceded procainamide in patients
with atrial arrhythmias. Cardiotonic glycosides may induce sufficient increase in atrial contraction to dislodge atrial
mural emboli, with subsequent pulmonary embolism.
- Therapeutic procainamide blood levels are reached in approximately 24 h if kidney function is normal but are delayed in presence
of renal impairment.
Patient & Family Education
- Keep a record of weekly weight. Notify physician if weight gain of 1 kg (2 lb) or more is accompanied by local edema.
- Record and report date, time, and duration of fibrillation episodes when taking maintenance doses: Light-headedness, giddiness,
weakness, or faintness.
- Keep a record of pulse rates. Report to physician changes in rate or quality.
- Report to physician signs of reduced procainamide control: Weakness, irregular pulse, unexplained fatigability, anxiety.
- Do not double dose or change an interval because a previous dose was missed. Take procainamide at evenly spaced intervals
around the clock unless otherwise prescribed.