What is procainamide, and how does it work (mechanism of action)?
Procainamide is an injectable antiarrhythmic
drug that is used to correct disturbances in the heart's rhythm. Three
actions are responsible for its ability to correct disturbances of rhythm and
prevent their recurrence. Procainamide decreases the speed of electrical
conduction through the heart muscle, prolongs the electrical phase during which
the heart's muscle cells can be electrically stimulated, and prolongs the
recovery period during which the heart muscle cells cannot be stimulated.
Procainamide was approved for use by the FDA in 1950.
What brand names are available for procainamide?
Pronestyl, Procan-SR, Procanbid (These brands no longer are available in the U.S.)
Is procainamide available as a generic drug?
GENERIC AVAILABLE: Yes
Do I need a prescription for procainamide?
What are the side effects of procainamide?
A severe reduction in
white blood cell
count occurs relatively rarely with procainamide therapy and is more common
with the sustained-release preparations. This side effect has caused death. For
this reason, patients on sustained-release procainamide get a
blood count test (CBC) every 2 weeks for the first 3 months of treatment. A syndrome
and/or skin rash can occur with procainamide. The lupus-like syndrome is
reversible after stopping the drug. Rarely, procainamide can cause
What is the dosage for procainamide?
An intravenous dose of 15 to 18 mg/kg may be administered over 25-30
minutes to adults. The initial dose is followed with a maintenance dose of 1-4
mg/min. Dose adjustments (reductions) are recommended in patients with liver and
It can also be given by intramuscular (IM) injection. The IM dose is 0.5 to 1
g every 4 to 8 hours.
Dosing in children is based on both their age and weight. Infants usually
need a loading dose. Depending on age and weight, a loading dose of the drug may
be recommended; in addition, IV or IM dosing may be used. Pediatric specialists,
or in an emergency, an Emergency Medicine physician should calculate the dose
and route of administration.
Which drugs or supplements interact with procainamide?
increases the blood concentrations of procainamide by either decreasing the
kidneys or the liver's abilities to remove procainamide. Combining procainamide
with thioridazine (Mellaril), pimozide (Orap), quinolones for example,
tricyclic antidepressants for example,
(Endep, Elavil), and
may increase the risk of abnormal heart beats because these drugs may also
prolong the recovery period of the heart. Concurrent administration of
procainamide with other anti-arrhythmics can result in additive or antagonistic
effects on the heart.
In the U.S., 1 in every 4 deaths is caused by heart disease.
Is procainamide safe to take if I’m pregnant or breastfeeding?
What else should I know about procainamide?
What preparations of procainamide are available?
Injection: 100 and 500 mg/ml.
How should I keep procainamide stored?
Procainamide may be kept at room temperature. If diluted, it is
stable for 24 hours at room temperature or seven days if refrigerated at 2 C to 8
C (35 F to 46 F).