Quinidine

Quinidine is used to help maintain a normal heartbeat in individuals with specific heart rhythm disorders, typically after other treatments have not worked. Quinidine has not been shown to reduce the risks of stroke or death.

Quinidine is also used to treat a severe form of malaria.

Quinidine may also be used for other reasons not mentioned in this medication guide.

quinidine may increase your risk of death, especially if you have heart problems affecting the tissues or valves of your heart (including heart problems you may have been born with). Ask your doctor about the risks and benefits of using quinidine.

Although quinidine can help reduce episodes of irregular heart rhythm, it may also increase your risk of death. This risk may be higher if you have heart problems affecting the tissues or valves of your heart, including congenital heart issues. Discuss the risks and benefits of using quinidine with your doctor.

You should not use quinidine if you are allergic to it, or if you have:

• a serious heart condition called "AV block" (unless you have a pacemaker);
• myasthenia gravis; or
• a history of bruising or bleeding after using quinidine or quinine.

Inform your doctor if you have ever experienced:

• a heart condition called "sick sinus syndrome";
• slow heartbeats;
• congestive heart failure;
• a heart valve disorder, a hole in your heart, an enlarged heart, or mitral valve prolapse;
• long QT syndrome (in you or a family member);
• Marfan syndrome;
• heart rhythm problems with past use of quinidine;
• liver or kidney disease; or
• an electrolyte imbalance (such as low levels of potassium or magnesium in your blood).

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

You should not breastfeed while using quinidine.

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

Quinidine may cause serious side effects. Call your doctor right away if you experience:

• fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (feeling like you might faint);
• vomiting and diarrhea;
• confusion, ringing in your ears, hearing loss;
• severe eye redness, vision problems, increased sensitivity to light;
• wheezing, chest tightness, trouble breathing;
• easy bruising, unusual bleeding;
• pale or yellowed skin, stomach pain (upper right side), dark urine;
• fever, chills, sore throat, mouth sores, swollen glands;
• skin itching, flaking, blistering, peeling, or rash on your cheeks or arms that gets worse in sunlight;
• muscle or joint pain; or
• dry mouth, difficulty swallowing.

Common side effects of quinidine may include:

• chest pain, pounding heartbeats;
• dizziness;
• heartburn, nausea, vomiting, diarrhea;
• flushing (sudden warmth, redness, or tingling sensation);
• feeling weak or tired; or
• pain or tenderness at the injection site (which may last for several weeks).

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

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed. Your blood pressure and heart rate should be monitored in a hospital or clinic setting when you start using quinidine, and whenever your dose is changed.

Do not change your medication dose or schedule without your doctor's advice.

Quinidine oral is taken by mouth. Quinidine injection is given as an infusion into a vein. A healthcare provider will give you this injection if you are unable to take the medicine by mouth.

Do not crush or chew an extended-release tablet. Swallow it whole. You may break the tablet in half if your doctor instructs you to.

When quinidine is given to treat malaria, you may also be given antibiotic medication. Keep using the antibiotic for as long as your doctor has prescribed.

Store at room temperature away from moisture and heat.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Since you will get quinidine injection in a clinical setting, you are not likely to miss a dose.

Seek emergency medical help or call the Poison Help line at 1-800-222-1222. Taking too much quinidine can be deadly.

An overdose can lead to vomiting, diarrhea, ringing in your ears, hearing loss, severe dizziness, double vision, confusion, irregular heartbeats, or a feeling of faintness.

Grapefruit may interact with oral quinidine and cause unwanted side effects. Do not use grapefruit products.

Sometimes it is not safe to use certain medications together. Some drugs can change the amount of other drugs in your blood, which may increase side effects or reduce how well the medications work.

Many drugs can affect quinidine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are included here. Tell your doctor about all your current medicines and any medicine you begin or stop using.