Though procainamide often gives great benefits to people with irregular heartbeat, it may infrequently cause a serious (possibly fatal) new irregular heartbeat. Therefore, procainamide treatment is usually started in the hospital so that your doctor can check on you and provide emergency medical treatment if needed. Talk with your doctor about the benefits and risks of taking procainamide.
This medication may rarely decrease bone marrow function, an effect that may lead to a low number of blood cells such as red cells, white cells, and platelets. This effect can cause anemia, decrease your body's ability to fight a serious (possibly fatal) infection, or cause easy bruising/bleeding. Tell your doctor right away if you develop signs of anemia (such as severe tiredness, pale skin, shortness of breath), signs of infection (such as fever, chills, persistent sore throat, mouth sores), or easy bruising/bleeding.
If you take procainamide for a long time, your body may start to make a certain type of antibody (antinuclear antibody-ANA) that may make you ill. Tell your doctor right away if you have aching/swollen joints, muscle aches, rash on your nose and cheeks, skin sores/changes, fever, severe tiredness, or painful breathing. Your doctor will do a blood test to check if you have this antibody. If you do, your doctor will discuss with you if continued use of procainamide is right for you.Who should not take Sub-Quin?
This medication is used to treat a certain serious, life-threatening irregular heartbeat (ventricular tachycardia). It is used to restore normal heart rhythm and to keep a regular, steady heartbeat. Procainamide is known as an anti-arrhythmic drug. It works by blocking certain electrical signals in the heart that can cause an irregular heartbeat.
Take this medication by mouth with or without food as directed by your doctor.
For extended-release tablets: Do not crush or chew extended-release tablets. Doing so can release all of the drug at once, increasing the risk of side effects. Also, do not split the tablets unless they have a score line and your doctor or pharmacist tells you to do so. Swallow the whole or split tablet without crushing or chewing. You may see the empty tablet shell in your stool. This is harmless because your body has already absorbed the medication.
The dosage is based on your medical condition and response to treatment.
This medication works best when the amount of drug in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals. To help you remember, take it at the same times each day.
Tell your doctor if your condition does not improve or if it worsens.
See also Warning section.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication for a longer time may develop serious side effects. Careful monitoring by your doctor may decrease your risk.
Tell your doctor right away if you have any serious side effects, including: signs of liver problems (such as persistent nausea/vomiting, stomach/abdominal pain, yellowing eyes/skin, dark urine), mental/mood changes (such as depression, confusion, unusual thoughts/behavior, hallucinations), new/worsening symptoms of heart failure (such as swelling ankles/feet, trouble breathing, unusual tiredness).
Get medical help right away if you have any very serious side effects, including: severe dizziness, fainting, sudden change in heartbeat (unusually faster/slower/more irregular), chest pain, seizures.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before taking procainamide, tell your doctor or pharmacist if you are allergic to it; or to local anesthetic drugs (such as procaine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: certain irregular heartbeat problems (second- or third-degree atrioventricular block or bundle branch block, unless you have a heart pacemaker), new or recent heart attack, worsening chest pain (angina), low blood pressure, lupus, kidney problems, liver problems, myasthenia gravis, blood/bone marrow problems (such as low red/white blood cells and platelets).
This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.
Procainamide may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can infrequently result in serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.
The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using procainamide, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death).
Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using procainamide safely.
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Older adults may be more sensitive to the side effects of this drug, especially QT prolongation (see above).
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
This medication passes into breast milk in small amounts. Consult your doctor before breast-feeding.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
A product that may interact with this drug is: fingolimod.
Alcohol may lower the amount of procainamide in your bloodstream. Limit alcoholic beverages.
Certain drugs (lidocaine, meprobamate, propranolol) may interfere with laboratory blood tests for procainamide. Make sure laboratory personnel and all your doctors know if you are taking any of these medications.
If overdose is suspected, contact a poison control center or emergency room immediately. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: sudden fast/pounding heartbeat, severe dizziness, fainting.
Do not share this medication with others.
Laboratory and/or medical tests (such as EKG, procainamide levels, blood counts, liver/kidney tests, antinuclear antibody) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
MEDICAL ALERT: Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).
Information last revised January 2015. Copyright(c) 2015 First Databank, Inc.
Sorry. No images are available for this medication.
With WebMD's Medicine Cabinet, you can check interactions with drugs.Go to medicine cabinet