In patients with symptomatic atrial fibrillation/flutter whose symptoms are not adequately controlled by measures that reduce the rate of ventricular response, quinidine sulfate is indicated as a means of restoring normal sinus rhythm.

If this use of quinidine sulfate does not restore sinus rhythm within a reasonable time (see DOSAGE and ADMINISTRATION), then quinidine sulfate should be discontinued.

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Cardiac Flutter --

Atrial Flutter -- Rapid, irregular atrial contractions caused by a block of electrical impulse conduction in the right atrium and a reentrant wave front traveling up the inter-atrial septum and down the right atrial free wall or vice versa. Unlike ATRIAL FIBRILLATION which is caused by abnormal impulse generation, typical atrial flutter is caused by abnormal impulse conduction. As in atrial fibrillation, patients with atrial flutter cannot effectively pump blood into the lower chambers of the heart (HEART VENTRICLES).

Symptoms -- An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

Quinidine is contraindicated in patients who are known to be allergic to it, or who have developed thrombocytopenic purpura during prior therapy with quinidine or quinine.In the absence of a functioning artificial pacemaker, quinidine is also contraindicated in any patient whose cardiac rhythm is dependent upon a junctional or idioventricular pacemaker, including patients in complete atrioventricular block.Quinidine is also contraindicated in patients who, like those with myasthenia gravis, might be adversely affected by an anticholinergic agent.

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Thrombocytopenic purpura -- Any form of purpura in which the PLATELET COUNT is decreased. Many forms are thought to be caused by immunological mechanisms.

Complete atrioventricular block -- Complete failure of atrial electrical impulse conduction through the AV node to the ventricles.

Myasthenia Gravis -- A disorder of neuromuscular transmission characterized by weakness of cranial and skeletal muscles. Autoantibodies directed against acetylcholine receptors damage the motor endplate portion of the NEUROMUSCULAR JUNCTION, impairing the transmission of impulses to skeletal muscles. Clinical manifestations may include diplopia, ptosis, and weakness of facial, bulbar, respiratory, and proximal limb muscles. The disease may remain limited to the ocular muscles. THYMOMA is commonly associated with this condition. (Adams et al., Principles of Neurology, 6th ed, p1459)

In many trials of antiarrhythmic therapy for non-life-threatening arrhythmias, active antiarrhythmic therapy has resulted in increased mortality; the risk of active therapy is probably greatest in patients with structural heart disease.In the case of quinidine used to prevent or defer recurrence of atrial flutter/fibrillation, the best available data come from a metaanalysis described under CLINICAL PHARMACOLOGY/Clinical Effects above.

In the patients studied in the trials there analyzed, the mortality associated with the use of quinidine was more than three times as great as the mortality associated with the use of placebo.Another metaanalysis, also described under CLINICAL PHARMACOLOGY/Clinical Effects, showed that in patients with various non-life-threatening ventricular arrhythmias, the mortality associated with the use of quinidine was consistently greater than that associated with the use of any of a variety of alternative antiarrhythmics.

The following US Branded drugs contain Quinidine Sulfate

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CIN-QUIN -- SOLVAY PHARMACEUTICALS

QUINIDEX -- WYETH PHARMACEUTICALS INC

QUINORA -- KEY PHARMACEUTICALS INC SUB SCHERING PLOUGH CORP

QUINORA -- SCHERING CORP