Procainamide
Looking up MedlinePlus…
From MedlinePlus, U.S. National Library of Medicine
Boxed warning
WARNING: The prolonged administration of procainamide often leads to the development of a positive anti-nuclear antibody (ANA) test, with or without symptoms of a lupus erythematosus-like syndrome. If a positive ANA titer develops, the benefit versus risks of continued procainamide therapy should be assessed.
Mortality: In the National Heart, Lung and Blood Institute's Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multicentered, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had a myocardial infarction more than six days but less than two years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to matched placebo-treated group (3.0%). The average duration of treatment with encainide or flecainide in this study was ten months.
The applicability of the CAST results to other populations (e.g., those without recent myocardial infarctions) is uncertain. Considering the known proarrhythmic properties of procainamide and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, the use of procainamide as well as other antiarrhythmic agents should be reserved for patients with life-threatening ventricular arrhythmias. Blood Dyscrasias: Agranulocytosis, bone marrow depression, neutropenia, hypoplastic anemia and thrombocytopenia in patients receiving procainamide hydrochloride have been reported at a rate of approximately 0.5%.
Most of these patients received procainamide within the recommended dosage range. Fatalities have occurred (with approximately 20–25 percent mortality in reported cases of agranulocytosis). Since most of these events have been noted during the first 12 weeks of therapy, it is recommended that complete blood counts including white cell, differential and platelet counts be performed at weekly intervals for the first three months of therapy, and periodically thereafter. Complete blood counts should be performed promptly if the patient develops any signs of infection (such as fever, chills, sore throat or stomatitis), bruising or bleeding.
If any of these hematologic disorders are identified, procainamide therapy should be discontinued. Blood counts usually return to normal within one month of discontinuation. Caution should be used in patients with pre-existing marrow failure or cytopenia of any type. (See ADVERSE REACTIONS ).
Dosing in kidney impairment
This amount should be divided into fractional doses of one-eighth to one-quarter to be injected intramuscularly every three to six hours until oral therapy is possible. If more than three injections are given, the physician may wish to assess patient factors such as age and renal function (see below), clinical response and, if available, blood levels of PA and NAPA in adjusting further doses for that individual.
Advancing age reduces the renal excretion of PA and NAPA independently of reductions in creatinine clearance; compared to normal young adults, there is approximately 25 percent reduction at age 50 and 50 percent at age 75. Intravenous therapy should be terminated if persistent conduction disturbances or hypotension develop.
| DILUTIONS AND RATES FOR INTRAVENOUS INFUSIONS* Procainamide Hydrochloride Injection, USP | ||||
| Final Concentration | Infusion Volume† | Procainamide Hydrochloride To Be Added | Infusion Rate | |
| Initial Loading Infusion | 20 mg/mL | 50 mL | 1000 mg | 1 mL/min (for up to 25–30 min*) |
| Maintenance Infusion | 2 mg/mLor4 mg/mL | 500 mL 250 mL | 1000 mg 1000 mg | 1 to 3 mL/min 0.5 to 1.5 mL/min |
| The maintenance infusion rates are calculated to deliver 2 to 6 mg per minute, depending on body weight, renal elimination rate, and steady-state plasma level needed to maintain control of the arrhythmia*. The 4 mg/mL maintenance concentration may be preferred if total infused volume must be limited. | ||||
| †(All infusions should be made up to final volume with 5% Dextrose Injection, USP.) *Please see text under DOSAGE AND ADMINISTRATION for further details. The flow rate of any intravenous procainamide infusion must be monitored closely to avoid transiently high plasma levels and possible hypotension (see PRECAUTIONS). | ||||
Preparation and administration
Prepare this dose
Your numbers for procainamide. Take vial strength, diluent, and limits from the label below.
Enter a dose to see draw volume, final concentration, and rates.
For treatment of arrhythmias associated with anesthesia or surgical operation, the suggested dose is 100 to 500 mg by intramuscular injection. Intravenous administration of Procainamide Hydrochloride Injection should be done cautiously to avoid a possible hypotensive response (see PRECAUTIONS and OVERDOSAGE ). Initial arrhythmia control, under ECG monitoring, may usually be accomplished safely within a half-hour by either of the two methods which follows: a) Direct injection into a vein or into tubing of an established infusion line should be done slowly at a rate not to exceed 50 mg per minute.
It is advisable to dilute the 100 mg/mL concentration of procainamide hydrochloride prior to intravenous injection to facilitate control of dosage rate. Doses of 100 mg may be administered every 5 minutes at this rate until the arrhythmia is suppressed or until 500 mg has been administered, after which it is advisable to wait 10 minutes or longer to allow for more distribution into tissues before resuming. b) Alternatively, a loading infusion containing 20 mg of Procainamide Hydrochloride per mL (1 g diluted to 50 mL with 5% Dextrose Injection, USP) may be administered at a constant rate of 1 mL per minute for 25 to 30 minutes to deliver 500 to 600 mg of PA.
Some effects may be seen after infusion of the first 100 or 200 mg; it is unusual to require more than 600 mg to achieve satisfactory antiarrhythmic effects. The maximum advisable dosage to be given either by repeated bolus injections or such loading infusion is 1 g. To maintain therapeutic levels, a more dilute intravenous infusion at a concentration of 2 mg/mL is convenient (1000 mg procainamide HCl in 500 mL of 5% Dextrose Injection, USP), and may be administered at 1 to 3 mL/minute.
A maintenance infusion rate of 50 mcg/min/kg body weight to a person with a normal renal PA elimination half-time of three hours may be expected to produce a plasma level of approximately 6.5 mcg/mL. Since the principal route for elimination of PA and NAPA is renal excretion, reduced excretion will prolong the half-life of elimination and lower the dose rate needed to maintain therapeutic levels.
| DILUTIONS AND RATES FOR INTRAVENOUS INFUSIONS* Procainamide Hydrochloride Injection, USP | ||||
| Final Concentration | Infusion Volume† | Procainamide Hydrochloride To Be Added | Infusion Rate | |
| Initial Loading Infusion | 20 mg/mL | 50 mL | 1000 mg | 1 mL/min (for up to 25–30 min*) |
| Maintenance Infusion | 2 mg/mLor4 mg/mL | 500 mL 250 mL | 1000 mg 1000 mg | 1 to 3 mL/min 0.5 to 1.5 mL/min |
| The maintenance infusion rates are calculated to deliver 2 to 6 mg per minute, depending on body weight, renal elimination rate, and steady-state plasma level needed to maintain control of the arrhythmia*. The 4 mg/mL maintenance concentration may be preferred if total infused volume must be limited. | ||||
| †(All infusions should be made up to final volume with 5% Dextrose Injection, USP.) *Please see text under DOSAGE AND ADMINISTRATION for further details. The flow rate of any intravenous procainamide infusion must be monitored closely to avoid transiently high plasma levels and possible hypotension (see PRECAUTIONS). | ||||
Drug interactions
Check procainamide against a medication listLabel text (1 paragraph)
Drug Interactions If other antiarrhythmic drugs are being used, additive effects on the heart may occur with PA administration, and dosage reduction may be necessary (see WARNINGS ). Anticholinergic drugs administered concurrently with PA may produce additive antivagal effects on A-V nodal conduction, although this is not as well documented for PA as for quinidine. Patients taking PA who require neuromuscular blocking agents such as succinylcholine may require less than usual doses of the latter, due to PA effects on reducing acetylcholine release.
Contraindications
Complete Heart Block: Procainamide should not be administered to patients with complete heart block because of its effects in suppressing nodal or ventricular pacemakers and the hazard of asystole. It may be difficult to recognize complete heart block in patients with ventricular tachycardia, but if significant slowing of ventricular rate occurs during PA treatment without evidence of A-V conduction appearing, PA should be stopped. In cases of second degree A-V block or various types of hemiblock, PA should be avoided or discontinued because of the possibility of increased severity of block, unless the ventricular rate is controlled by an electrical pacemaker.
Idiosyncratic Hypersensitivity: In patients sensitive to procaine or other ester-type local anesthetics, cross sensitivity to PA is unlikely. However, it should be borne in mind, and PA should not be used if it produces acute allergic dermatitis, asthma, or anaphylactic symptoms. Lupus Erythematosus: An established diagnosis of systemic lupus erythematosus is a contraindication to PA therapy, since aggravation of symptoms is highly likely.
Torsades de Pointes: In the unusual ventricular arrhythmia called "les torsades de pointes" (twistings of the points), characterized by alternation of one or more ventricular premature beats in the directions of the QRS complexes on ECG in persons with prolonged Q-T and often enhanced U waves, Group 1A antiarrhythmic drugs are contraindicated. Administration of PA in such cases may aggravate this special type of ventricular extrasystole or tachycardia instead of suppressing it.
Pregnancy and lactation
Lactation
Nursing Mothers Both PA and NAPA are excreted in human milk, absorbed by the nursing infant. Because of the potential for serious adverse reactions in nursing infants, a decision to discontinue nursing or the drug should be made, taking into account the importance of the drug to the mother.
For breastfeeding, also see LactMed (National Library of Medicine), which summarizes milk levels and infant effects.
Supply and cost
Drug shortage status
Recalls (last 24 months)
Therapeutic equivalence (Orange Book)
Price ladder
Not the price at the counterThese are not what a patient pays at the pharmacy counter. They are what pharmacies, health plans, and government buyers pay, before manufacturer rebates. A patient's cost depends on their insurance (copay, coinsurance, or deductible) or the pharmacy's cash price.