Drugs A - Z

Procainamide Hydrochloride Oral tablet, extended release

It helps make your heart beat regularly

Generic Name: procainamide

Brand Names: Pronestyl, Procan Sr, Procainamide Hydrochloride Sr, Procanbid, Pronestyl-Sr

There is an FDA Alert for this drug. Click here to view it.

    Positive ANA Titer
  • Prolonged use often results in development of positive antinuclear antibody (ANA) titers.
  • Symptoms of systemic lupus erythematosus (SLE)-like syndrome may or may not accompany ANA titers.
  • Assess benefits versus risks of continued therapy if positive ANA titer develops.

  • Excessive mortality or nonfatal cardiac arrest rate (7.7%) in encainide- or flecainide-treated patients with asymptomatic non-life-threatening ventricular arrhythmias (with MI history >6 days but <2 years) in NHLBI's long-term CAST study relative to placebo.
  • Applicability of CAST findings to other populations (e.g., those without recent MI) uncertain.
  • Because of procainamide's proarrhythmic properties and lack of evidence of improved survival for any antiarrhythmic drug, reserve procainamide for life-threatening ventricular arrhythmias.

    Blood Dyscrasias
  • Agranulocytosis, bone marrow depression, neutropenia, hemoplastic anemia, and thrombocytopenia occur in approximately 0.5% of procainamide-treated patients, usually at recommended dosages.
  • Potentially fatal (e.g., in 20–25% of agranulocytosis cases).
  • Usually noted during the initial 12 weeks of therapy.
  • Perform CBCs, including leukocyte, differential, and platelet counts, at weekly intervals for the first 3 months of therapy and periodically thereafter.
  • Perform CBC promptly if any sign of infection (e.g., fever, chills, sore throat, stomatitis), bruising, or bleeding develops.
  • Discontinue procainamide if any of these hematologic disorders develops.
  • Blood cell counts usually return to normal 1 month after procainamide discontinuance.
  • Exercise caution in preexisting marrow failure or cytopenia of any type.

What is this medicine?

PROCAINAMIDE (proe kane A mide) is an antiarrhythmic drug. It helps make your heart beat regularly. This medicine also helps to slow rapid heartbeats.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
  • anemia or blood disease
  • heart disease or previous heart attack
  • immune system problems, like lupus
  • kidney disease
  • liver disease
  • low blood pressure
  • myasthenia gravis
  • an unusual or allergic reaction to procainamide, procaine, other medicines, foods, dyes, or preservatives
  • pregnant or trying to get pregnant
  • breast-feeding

How should I use this medicine?

Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. Do not cut, crush or chew this medicine. Take your doses at regular intervals. Do not take your medicine more often than directed. Do not stop taking this medicine suddenly. This may cause serious, heart-related side effects. Your doctor will tell you how much medicine to take. If your doctor wants you to stop the medicine, the dose will be slowly lowered over time to avoid any side effects.

Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medicine?

Do not take this medicine with any of the following medications:
  • abarelix
  • amoxapine
  • apomorphine
  • arsenic trioxide
  • certain macrolide antibiotics
  • certain quinolone antibiotics
  • cisapride
  • droperidol
  • haloperidol
  • hawthorn
  • levomethadyl
  • maprotiline
  • medicines for malaria like chloroquine and halofantrine
  • medicines for mental depression such as tricyclic antidepressants
  • methadone
  • pentamidine
  • other medicines to control heart rhythm
  • phenothiazines like chlorpromazine, mesoridazine, and thioridazine
  • pimozide
  • probucol
  • ranolazine
  • sertindole
  • vardenafil
  • ziprasidone

This medicine may also interact with the following medications:

  • cimetidine
  • ranitidine
  • succinylcholine
  • trimethoprim

What should I watch for while using this medicine?

Your condition will be monitored closely when you first begin therapy. Often, this drug is first started in a hospital or other monitored health care setting. Once you are on maintenance therapy, visit your doctor or health care professional for regular checks on your progress. Wear a medical ID bracelet or chain, and carry a card that describes your disease and details of your medicine and dosage times.

Check your heart rate and blood pressure regularly while you are taking this medicine. Ask your doctor or health care professional what your heart rate and blood pressure should be, and when you should contact him or her. Your doctor or health care professional also may schedule regular blood tests and electrocardiograms to check your progress.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.

The tablet shell for some brands of this medicine does not dissolve. This is normal. The tablet shell may appear whole in the stool. This is not a cause for concern.

Last Updated: July 20, 2009
Licensed from
The Healthline Site, its content, such as text, graphics, images, search results, and other material contained on the Healthline Site ("Content"), its services, and any information or material posted on the Healthline Site by third parties are provided for informational purposes only. None of the foregoing is a substitute for professional medical advice, examination, diagnosis, or treatment. Always seek the advice of a physician or other qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on the Healthline Site. If you think you may have a medical emergency, call your doctor or 911 immediately. Please read the Terms of Service for more information regarding use of the Healthline Site.