Studies have shown that some antiarrhythmic drugs may increase the risk of death, especially if you have had a previous heart attack. This information also may apply to quinidine. Quinidine usually is used only to treat life-threatening arrhythmias.
Why is this medication prescribed?
Quinidine is used to treat abnormal heart rhythms. It works by making your heart more resistant to abnormal activity. Quinidine is also used to treat malaria.
This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
How should this medicine be used?
Quinidine comes as a tablet to take by mouth. Immediate-acting quinidine usually is taken three or four times a day. The extended-release (long-acting) product usually is taken two or three times a day. Do not cut, crush, or chew extended-release tablets; swallow them whole.
Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take quinidine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Quinidine helps control your condition but will not cure it. Continue to take quinidine even if you feel well. Do not stop taking quinidine without talking to your doctor.
What special precautions should I follow?
Before taking quinidine,
- tell your doctor and pharmacist if you are allergic to quinidine, quinine, or any other drugs.
- tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially anticoagulants ('blood thinners') such as warfarin (Coumadin); antidepressants; cimetidine (Tagamet); codeine products; diltiazem (Cardizem, Dilacor, Tiazac); medication for heart disease or high blood pressure; medications for seizures, sleep, or an infection; and vitamins.
- tell your doctor if you have an infection or have or have ever had myasthenia gravis; heart, kidney, or liver disease; or muscle weakness.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking quinidine, call your doctor.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking quinidine.
- you should know that this drug may make you dizzy. Do not drive a car or operate machinery until you know how this drug affects you.
- remember that alcohol can add to the dizziness caused by this drug.
- talk to your doctor about the use of cigarettes and caffeine-containing beverages. These products may increase the irritability of your heart and interfere with the action of quinidine.
- do not change brands of medication without talking to your doctor.
What special dietary instructions should I follow?
Avoid drinking grapefruit juice while taking quinidine. Do not change the amount of salt in your diet without talking to your doctor.
What should I do if I forget a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?
Quinidine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- stomach pain and cramps
- dizziness or lightheadedness
- vision changes
- difficulty sleeping
If you experience any of the following symptoms, call your doctor immediately:
- irregular heartbeat
- chest pain
- skin rash
- hearing changes (ringing or loss of hearing)
- vision changes (blurred or light sensitivity)
- unusual bleeding or bruising
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online () or by phone (1-800-332-1088).
What should I know about storage and disposal of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website () for more information if you do not have access to a take-back program.
It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach.
In case of emergency/overdose
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at . If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.
What other information should I know?
Keep all appointments with your doctor and the laboratory. Your doctor will need to determine your response to quinidine.
Take quinidine at the same time each day in regularly spaced intervals. Changing the time of your doses prevents quinidine from working effectively.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
¶ This branded product is no longer on the market. Generic alternatives may be available.