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Quinidine Sulfate

Quinidine is used to correct heart rhythm disturbances and is an antiarrhythmic medication. Three actions are responsible for quinidine's ability to stop heart rhythm disturbances (arrhythmias) and prevent their recurrence. Quinidine decreases the speed of electrical conduction in the heart muscle. It prolongs the electrical phase during which heart muscle cells become electrically stimulated (action potential) and prolongs the recovery period during which the heart muscle cells cannot be stimulated (refractory period).

Quinidine Sulfate Dosage

• The usual dosage is 300 milligrams quinidine every 8 to 12 hours.

Uses of Quinidine Sulfate

Quinidine corrects certain abnormal heart rhythms, including atrial fibrillation or flutter and life-threatening ventricular arrhythmias. It is usually prescribed only after other treatments have failed. If your condition does not improve after a reasonable period of time, your doctor may discontinue this medication and try other ways of restoring normal rhythm.

Side Effects of Quinidine Sulfate

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking quinidine. Side effects include:

• Abdominal pain, diarrhea, hepatitis, inflammation of the esophagus (gullet), loss of appetite, nausea, vomiting .
• Another possible side effect is a sensitivity reaction called cinchonism. Symptoms include blurred or double vision, confusion, delirium, diarrhea, headache, intolerance to light, hearing loss, ringing in the ears, vertigo, and vomiting.

Warnings and precautions before taking Quinidine Sulfate:

• Remember, too, that under certain conditions (slow heart rate, low potassium or magnesium levels) quinidine can cause certain types of heart irregularity. It can also cause the condition known as heart block, and should be used with caution if you have partial heart block.
• Also use quinidine cautiously if you have kidney or liver disease. Your doctor will check your blood count and liver and kidney function periodically during long-term therapy.
• The effects of Quinidine during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, tell your doctor immediately. Quinidine does appear in breast milk and can affect a nursing infant.

Drug Interaction :- If quinidine are taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining quinidine with the following:

• Amiodarone (Cordarone)
  Antispasmodic drugs such as Bentyl
• Diltiazem (Cardizem)
• Felodipine (Plendil)
• Haloperidol (Haldol)
• Ketoconazole (Nizoral)
• Major tranquilizers such as Mellaril and Thorazine
• Mexiletine (Mexitil)
• Nicardipine (Cardene)
• Codeine
• Verapamil (Calan)
• Warfarin (Coumadin)

Overdose

Any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical treatment immediately. Symptoms of quinidine overdose may include:

• Abnormal heart rhythms
• blurred or double vision
• confusion
• delirium
• diarrhea
• headache
• intolerance to light
• loss of hearing
• low blood pressure
• ringing in the ears
• vertigo
• vomiting