Procainamide (Pronestyl ®)
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| D5W (Listed as the primary solution in the package insert)
NS (Trissels and Lexi-comp: D5W - variable stability - procainamide may form an association complex with dextrose. Considered stable in NS.
Standard Dilutions [Amount of drug] [Infusion volume] [Infusion rate]
| Loading dose:
[1 gram] [50ml] [Max 25-50mg/min]
Stability / Miscellaneous
| EXP: 1 DAY (RT)
Label: Do not Refrigerate.
Side effects: Severe hypotension with rapid infusion; bradycardia, AV block, V-fib.
Alternate loading regimen: Add 1g/ 50 ml D5W - 20 mg/min x 25 to 30 min, wait 10 minutes for distribution, if no response continue with loading. (Note: 20 mg/min= 60 ml/hr - 1 g/50ml). If patient responds start maintenance infusion: 2 to 6 mg/min.
Stop infusion if QRS widens > 50%.
Steady state: 24hours (IV) / 48 hours (oral).
DOSAGE AND ADMINISTRATION
Intramuscular administration may be used as an alternative to the oral route for patients with less threatening arrhythmias but who are nauseated or vomiting, who are ordered to receive nothing by mouth preoperatively, or who may have malabsorptive problems. An initial daily dose of 50 mg per kg body weight may be estimated. 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. 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. 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 either the 100 mg/mL or the 500 mg/mL concentrations 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. If daily total fluid intake must be limited, a 4 mg/mL concentration (1 g of Procainamide Hydrochloride Injection in 250 mL of 5% Dextrose Injection, USP) administered at 0.5 to 1.5 mL/minute will deliver an equivalent 2 to 6 mg per minute. The amount needed in a given patient to maintain the therapeutic level should be assessed principally from the clinical response, and will depend upon the patient’s weight and age, renal elimination, hepatic acetylation rate, and cardiac status, but should be adjusted for each patient based upon close observation. 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. 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. As soon as the patient’s basic cardiac rhythm appears to be stabilized, oral antiarrhythmic maintenance therapy is preferable, if indicated and possible. A period of about three to four hours (one half-time for renal elimination, ordinarily) should elapse after the last intravenous dose before administering the first dose of Procainamide Hydrochloride tablets or capsules.
Parenteral drug products should be examined visually for particulate matter and discoloration (see HOW SUPPLIED) prior to administration.
1902 Fliptop Vial 100 mg/mL - 10 mL
1903 Fliptop Vial 500 mg/mL - 2 mL
The solutions, which are clear and colorless initially, may develop a slightly yellow color in time. This does not indicate a change which should preclude its use, but a solution any darker than light amber or otherwise discolored should not be used.
Store at controlled room temperature 15° to 30°C (59° to 86°F). [See USP.]
Source: [package insert]