Procainamide is used to help keep the heart beating normally in people with certain heart rhythm disorders of the ventricles (the lower chambers of the heart that allow blood to flow out of the heart).

Procainamide may also be used for purposes not listed in this medication guide.

Procainamide can cause serious side effects and is for use only to treat life-threatening heart rhythm problems. If you receive procainamide during an emergency, make sure any follow-up doctor knows you received procainamide.

Procainamide is injected into a muscle or vein by a healthcare provider.

Your heart function, blood pressure, and other vital signs will be watched closely.

You may get infections more easily, even serious or fatal infections. You may need medical tests for a short time after you receive procainamide injection.

You may not be able to receive procainamide if:

• you have a serious heart condition such as "AV block" (unless you have a pacemaker);

• you have lupus;

• you've had a heart attack;

• you have long QT syndrome and have had a condition called torsade de pointes; or

• you've had a severe allergic reaction to a numbing medicine.

If possible during an emergency, tell your medical caregivers if you've ever had:

• blood circulation problems;

• a heart attack or stroke;

• a weak immune system;

• kidney disease;

• myasthenia gravis;

• asthma or sulfite allergy; or

• an allergy to aspirin.

It is not known if procainamide will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Do not breastfeed.

In a medical setting you are not likely to miss a dose.

In a medical setting an overdose would be treated quickly.

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Tell your medical caregivers right away if you have:

• sudden fever, chills, sore throat, mouth sores, weakness;

• joint pain, muscle pain or weakness;

• wheezing, chest pain;

• easy bruising, pale or yellowed skin, dark colored urine;

• depression, dizziness, hallucinations;

• stomach pain, nausea, vomiting, diarrhea, loss of appetite; or

• lupus-like symptoms--joint pain or swelling, stomach pain, chest pain, shortness of breath, and a rash or patchy skin color that worsens in sunlight.

Common side effects of procainamide may include:

• stomach pain, loss of appetite, nausea, vomiting, diarrhea;

• dizziness, weakness, depressed mood;

• abnormal liver function tests; or

• rash or itching.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all other medicines you use, especially:

• digoxin (digitalis) or other heart rhythm medications;

• bronchodilator asthma medication;

• cold or allergy medicine (Benadryl and others);

• medicine to treat overactive bladder;

• medicine to treat Parkinson's disease; or

• medicine to treat stomach problems, motion sickness, or irritable bowel syndrome.

This list is not complete. Other drugs may affect procainamide, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.