Propafenone Hydrochloride Tablets

[Pharmacology and Toxicology] (1) This product belongs to the class Ic (i.e., directly acting on the cell membrane) antiarrhythmic drug. The experimental results of isolated animal myocardium indicate that at 0.5-1ug/min, it can reduce the depolarization effect during contraction, thereby prolonging conduction, slightly prolonging the duration of action potential and the effective refractory period, and can increase the threshold potential of myocardial cells, significantly reducing the spontaneous excitability of the myocardium. It acts on both the atrium and ventricle (mainly affecting the Purkinje fibers, with a smaller effect on the myocardium), and also on the formation and conduction of excitation. Clinical data show that the therapeutic dose (300mg orally and 30mg intravenously) can reduce the excitability of the myocardium, with a long-lasting effect, increasing PQ and QRS, and prolonging the effective refractory period of the atrium and atrioventricular node. It has an antagonistic effect on various types of experimental arrhythmias. The antiarrhythmic effect is related to its membrane stabilizing effect and competitive blocking effect. It also has a weak calcium antagonist effect (100 times weaker than verapamil), a mild myocardial inhibitory effect, increases end-diastolic blood pressure, and reduces stroke volume, and its effects are proportional to the dose used. It also has a mild antihypertensive and heart rate-reducing effect. (2) In vitro experiments have shown that propafenone can relax coronary artery and bronchial smooth muscle. (3) It has a local anesthetic effect similar to procaine. (4) Rats orally administered 180-360 mg/kg/day (12-24 times the maximum recommended dose for adults) for six months developed renal dysfunction, and inflammatory and non-inflammatory reactions were observed in the renal tubules and interstitium. Long-term administration of 19 times the maximum recommended dose for adults to rats revealed fatty degeneration of the liver. [Pharmacokinetics] After oral administration, it is well absorbed from the gastrointestinal tract. The antiarrhythmic effect reaches its peak 2 to 3 hours after taking it, and the effect can last for more than 8 hours. Its bioavailability is dose-dependent, such as 3.4% for 100 mg of propafenone, and 10.6% for 300 mg. This product has a high binding rate with plasma protein, reaching 93%. The bioavailability will increase with increasing dose. Decreased liver function will also increase the bioavailability of the drug. The clearance of propafenone slows down in severe liver damage. The pharmacokinetic curve of propafenone is nonlinear. The half-life of this drug is 3.5 to 4 hours. This product is excreted by the kidneys, mainly as metabolites, and a small part (1%) is the original form. It cannot be excreted through dialysis.

The main ingredient of this product and its chemical name are: 3-phenyl-1-[2-[3-(propylamino)-2-hydroxypropoxy]-phenyl]-1-propanone hydrochloride.

This product is white or off-white tablets.

Used for paroxysmal ventricular tachycardia and supraventricular tachycardia (including those with preexcitation syndrome).

Oral: 100-200 mg per time, 3-4 times a day. Therapeutic dose: 300-900 mg per day, divided into 4-6 doses. Maintenance dose: 300-600 mg per day, divided into 2-4 doses. Due to its local anesthetic effect, it is advisable to swallow it with drinks or food after meals and do not chew it.

(1) There are relatively few adverse reactions, the main ones being dry mouth and numbness of the tongue and lips, which may be due to its local anesthetic effect. In addition, early adverse reactions include headache, dizziness, and glaucoma, followed by gastrointestinal disorders such as nausea, vomiting, and constipation. Symptoms of atrioventricular block have also occurred. There are two reports of cholestatic liver damage after two weeks of continuous use. The activity of each enzyme returned to normal 2 to 4 weeks after discontinuation of the drug. It is believed that this pathological change is due to allergic reactions and individual factors. (2) During the trial, no damage to the lungs, liver, and hematopoietic system was observed. A few patients experienced mild reactions such as dry mouth, headache, dizziness, and gastrointestinal discomfort, which generally disappeared after discontinuation of the drug or reduction of the dosage. There are reports of atrioventricular conduction block, prolonged Q-T interval, mild prolongation of P-R interval, prolonged QRS time, etc. in individual patients.

It is contraindicated in patients with sinus node dysfunction without pacemaker protection, severe atrioventricular block, bilateral bundle branch block, severe congestive heart failure, cardiogenic shock, severe hypotension, and those who are allergic to the drug.

Precautions for children: The safety and effectiveness of this drug in children are not yet known. Precautions for pregnancy and lactation: Pregnant women should use it with caution. It is recommended that lactating women stop using it. Precautions for the elderly: There is no increase in age-related side effects when using this drug in elderly patients. However, elderly patients may experience a drop in blood pressure after taking the drug. In addition, elderly patients are prone to liver and kidney damage, so it should be used with caution. The effective drug dose for elderly patients is lower than normal.

Combination with quinidine can slow down the metabolic process. Combination with local anesthetics increases the occurrence of central nervous system side effects. Propafenone can increase serum digoxin concentrations in a dose-dependent manner. Combination with propranolol and metoprolol can significantly increase their plasma concentrations and elimination half-life, but has no effect on propafenone. Combination with warfarin can increase warfarin blood concentrations and prothrombin time. Combination with cimetidine can increase the steady-state level of propafenone in the blood, but has no effect on its electrophysiological parameters.

Keep away from light and store in a sealed container.

50mg

36 months

Changzhou Pharmaceutical Factory Co., Ltd.

• Founded in:

  2001-12-14

• Address:

  No. 518, Laodong East Road, Changzhou

• Tax NO.:

  91320400137158490L

• Registered Funds:

  108 million yuan

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