Quinidine sulfate tablets

This product is a Class Ia antiarrhythmic drug that has a direct effect on the cell membrane, mainly inhibiting the transmembrane movement of sodium ions and affecting the 0 phase of the action potential. It inhibits the autonomy of the myocardium, especially the autonomy of ectopic excitation points, reduces conduction velocity, prolongs the effective refractory period, reduces excitability, and prolongs the refractory period of the atria more significantly than the ventricles, shortens the refractory period of the atrioventricular junction, and increases the fibrillation threshold of the atrial and ventricular muscles. Secondly, it inhibits the influx of calcium ions and reduces myocardial contractility. It indirectly affects the heart through anticholinergic effects. Large doses can block α receptors, produce vasodilation and hypotension. The effective blood concentration of quinidine is 3~6mg/L, and serious adverse reactions may occur above 8mg/L.

The chemical name of this product is: (9S)-6′-methoxy-deoxycinchonin-9-ol sulfate dihydrate

This product is a sugar-coated tablet, which appears white after removing the sugar coating.

Oral administration is mainly suitable for the maintenance treatment of atrial fibrillation or atrial flutter after electrical cardioversion. Although it is effective for atrial premature beats, paroxysmal supraventricular tachycardia, preexcitation syndrome with supraventricular arrhythmia, ventricular premature beats, ventricular tachycardia, and has the effect of cardioverting atrial fibrillation or atrial flutter, it is rarely used now due to many adverse reactions. Intramuscular and intravenous injections are no longer used.

Adults should first try taking 0.2g to observe whether there are allergic and idiosyncratic reactions. Common dosage for adults: 0.2-0.3g at a time, 3-4 times a day. For cardioversion of atrial fibrillation or atrial flutter, 0.2g on the first day, once every 2 hours, for 5 consecutive times; if there are no adverse reactions, increase to 0.3g each time on the second day, and 0.4g each time on the third day, once every 2 hours, for 5 consecutive times. The total daily amount should not exceed 2.4g. After sinus rhythm is restored, change to a maintenance dose of 0.2-0.3g at a time, 3-4 times a day. The maximum dosage for adult prescription: 3g per day (generally not more than 2.4g per day), which should be given in divided doses.

This product has a low therapeutic index, and about 1/3 of patients experience adverse reactions. 1 Cardiovascular: This product has a proarrhythmic effect, causing cardiac arrest and conduction block, which is more common in patients with existing heart disease. Ventricular premature beats, ventricular tachycardia and ventricular fibrillation may also occur. The electrocardiogram may show a prolonged P-R interval and a widened QRS wave, which is generally related to the dose. It can significantly prolong the Q-T interval of the electrocardiogram, induce ventricular tachycardia (torsades de pointes) or ventricular fibrillation, and may stop spontaneously repeatedly, accompanied by syncope during attacks. This effect is unrelated to the dose and may occur when the blood drug concentration is still within the therapeutic range or below. This product can cause vasodilation and produce hypotension, and vasculitis may occur in some cases. 2 Gastrointestinal adverse reactions: very common. Including nausea

Patients who are allergic to the drug or who have developed thrombocytopenic purpura due to the drug are contraindicated to use the drug. The drug is contraindicated for patients with Ⅱ or Ⅲ degree atrioventricular block and sick syndrome without pacemaker protection.

Precautions for children: Common dosage for children: 6 mg/kg per dose, or 180 mg/m2 per body surface area, 3 to 5 times a day. The safety and effectiveness of quinidine in children with arrhythmias have not yet been determined. Precautions for pregnancy and lactation: There are no studies to confirm the safety and effectiveness of the drug in pregnant women. It is only used for pregnant women who must use quinidine. The drug can pass the placental barrier. The quinidine content in amniotic fluid is 3 times that in serum. The content of the drug in breast milk is slightly lower than its maternal serum content. Therefore, it is best not to take this drug for breastfeeding women. Precautions for the elderly: The safety and effectiveness of quinidine in elderly patients are not yet certain.

1. When used in combination with other antiarrhythmic drugs, the effects may be additive. Verapamil and amiodarone may increase the blood concentration of this product. 2. When used in combination with oral anticoagulants, prothrombin may be further reduced, and the binding of this product to proteins may also be reduced. Therefore, it is necessary to pay attention to adjusting the dosage during combined use and after drug withdrawal. 3. Phenobarbital and phenytoin may increase the liver metabolism of this product and shorten the plasma half-life. The dosage should be adjusted as appropriate. 4. This product may increase the serum concentration of digoxin to a toxic level, and may also increase the serum concentration of digitalis glycosides. Therefore, the blood concentration should be monitored and the dosage adjusted. This product may aggravate arrhythmias when digitalis is overdosed. 5. When used in combination with anticholinergics,

Keep in a light-proof and airtight container.

0.2g

24 months

China Resources Double-Crane Pharmaceutical Co., Ltd.

• Founded in:

  1997-05-16

• Address:

  No. 1, Lize East 2nd Road, Wangjing, Chaoyang District, Beijing

• Tax NO.:

  91110000633796475U

• Registered Funds:

  1,038,836,522 yuan

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