Digoxin

At therapeutic doses: 1. Positive inotropic effect: This product selectively binds to the Na--K ATPase of the myocardial cell membrane and inhibits the activity of the enzyme, impairing the active coupled transport of Na-K inside and outside the myocardial cell membrane, increasing the concentration of Na in myocardial cells, and thus making the NaCa2 exchange on the sarcolemma active, increasing the amount of Ca2 in the cytoplasm, and increasing the Ca2 reserve in the sarcoplasmic reticulum. When the myocardium is excited, there is more Ca2 release; the concentration of Ca2 in myocardial cells increases, stimulating myocardial contractile proteins and thus increasing myocardial contractility. 2. Negative frequency effect: Due to its positive inotropic effect, it increases the cardiac output of the failing heart, improves the hemodynamic state, eliminates the reflex increase of sympathetic nerve tension, and enhances vagal nerve tension, thereby slowing down the heart rate. In addition, at low doses, it increases the sensitivity of the sinoatrial node to vagal impulses, which can enhance its effect of slowing down the heart rate. Large doses (usually close to the toxic dose) can directly inhibit the sinoatrial node, atrioventricular node and His bundle, and present sinus bradycardia and varying degrees of atrioventricular conduction block. 3. Cardiac electrophysiological effects: Through direct effects on myocardial electrical activity and indirect effects on the vagus nerve, it reduces the autonomy of the sinoatrial node; improves the autonomy of Purkinje fibers; slows down the conduction velocity of the atrioventricular node, prolongs its effective refractory period, and leads to increased latent conduction of the atrioventricular node, which can slow down the ventricular rate of atrial fibrillation or atrial flutter; since this drug shortens the effective refractory period of the atrium, when used for atrial tachycardia and atrial flutter, it may lead to acceleration of the atrial rate and conversion of atrial flutter to atrial fibrillation; shortens the effective refractory period of Purkinje fibers.

Digoxin. Chemical name: 3β-[[O-2, O-dideoxy-β-D-ribo-hexopyranosyl-(1→4)-O-2, 6-dideoxy-β-D-ribo-hexopyranosyl-(1→4)-2, 6-dideoxy-β-D-ribo-hexopyranosyloxy]-12β, 14β-dihydroxy-5β-cardiosteroid-20(22)enolide.

This product is white tablets.

1. Used for acute and chronic heart failure such as hypertension, valvular heart disease, congenital heart disease, etc. It is especially suitable for heart failure with atrial fibrillation accompanied by rapid ventricular rate; it has poor efficacy for heart failure caused by cor pulmonale, severe myocardial ischemia, active myocarditis and extracardiac factors such as severe anemia, hypothyroidism and vitamin B1 deficiency; 2. Used to control the ventricular rate and supraventricular tachycardia of patients with atrial fibrillation and atrial flutter accompanied by rapid ventricular rate.

Common oral dose for adults: 0.125~0.5mg, once a day, steady-state blood concentration can be reached in 7 days; if the rapid loading dose is reached, 0.25mg can be administered every 6~8 hours, with a total dose of 0.75~1.25mg/day; maintenance dose, 0.125~0.5mg once a day. Common oral dose for children: total amount of this product, premature infants 0.02~0.03mg/kg; newborns under 1 month old 0.03~0.04mg/kg; 1 month to 2 years old, 0.05~0.06mg/kg; 2~5 years old, 0.03~0.04mg/kg; 5~10 years old, 0.02~0.035/kg; 10 years old or above, according to the common adult dose; total amount of this product is divided into 3 times or given every 6~8 hours. The maintenance dose is 1/5~1/3 of the total amount, divided into 2 times, once every 12 hours or once a day. In infants and young children (especially premature infants), the dose should be carefully titrated and the blood drug concentration and electrocardiogram should be closely monitored. In recent years, studies have shown that digoxin can reach a stable concentration in the body after 6~7 days of daily administration of a fixed dose and exert its full effect. Therefore, for those who are not in urgent condition but are prone to poisoning, daily administration of 5.5ug/kg can also achieve satisfactory therapeutic effects and reduce the incidence of poisoning.

1. Common adverse reactions include: proarrhythmic effects, poor appetite or nausea, vomiting (stimulation of the medullary center), lower abdominal pain, abnormal weakness, and tenderness. 2. Rare reactions include: blurred vision or color vision, such as yellow vision, green vision, diarrhea, and central nervous system reactions such as depression or confusion. 3. Rare reactions include: drowsiness, headache and rash, urticaria (allergic reaction). 4. Among the manifestations of digitalis poisoning, proarrhythmia is the most important, and the most common is ventricular premature beats, accounting for about 33% of proarrhythmic adverse reactions. The second is atrioventricular block, paroxysmal or accelerated junctional tachycardia, paroxysmal atrial tachycardia with atrioventricular block, ventricular tachycardia, sinus arrest, ventricular fibrillation, etc. Arrhythmias are more common in children than other reactions, but ventricular arrhythmias are less common than in adults. Newborns may have a prolonged P-R interval.

① Used in combination with calcium injection; ② Poisoning by any digitalis preparation; ③ Ventricular tachycardia, ventricular fibrillation; ④ Obstructive hypertrophic cardiomyopathy (can still be considered if accompanied by systolic dysfunction or atrial fibrillation); ⑤ Preexcitation syndrome with atrial fibrillation or flutter.

1. When used together with amphotericin B, corticosteroids or potassium-losing diuretics such as Bumetanide (the product is buturamine) and Ethacrynic Acid (ethacrynic acid), it can cause hypokalemia and lead to digitalis poisoning. 2. When used together with antacids (especially magnesium trisilicate) or antidiarrheal adsorbents such as white clay, pectin, colestyramine (cholestyramine) and other anion exchange resins, sulfasalazine or neomycin, and para-aminosalicylic acid, it can inhibit the absorption of digitalis cardiac glycosides and weaken the effect of cardiac glycosides. 3. When used with antiarrhythmic drugs, calcium salt injections, cocaine, pancuronium bromide (PancuroniumBromide, Pan Kelong, Bahuolang), rauwolfia alkaloids, succinylcholine (Scoline; SuxamethoniumChloride) or adrenergic drugs, arrhythmias may occur due to additive effects. 4. The use of digitalis in patients with severe or complete atrioventricular block and normal blood potassium. Patients should not use potassium salts at the same time, but when thiazide diuretics are used with this product, potassium salts are often given to prevent hypokalemia. 5. The use of beta-blockers with this product may cause severe bradycardia in atrioventricular block, which should be taken seriously. However, it does not rule out the use of beta-blockers for supraventricular tachyarrhythmias where digitalis cannot control the ventricular rate. 6. When used with quinidine, the blood concentration of this product can be increased by about one-fold. The degree of increase is related to the dosage of quinidine, and can even reach the toxic concentration. Even if digoxin is discontinued, its blood concentration continues to rise. This is because quinidine replaces digoxin from tissue binding and reduces its distribution volume. When the two drugs are used together, the dosage of digoxin should be reduced by 1/2-1/3. 7. When used in combination with verapamil, diltiazem, and amiodarone, the blood concentration of digoxin is increased due to the reduction of the renal and systemic clearance rate of digoxin, which can cause severe bradycardia. 8. Spironolactone can prolong the half-life of this product, and the dosage or dosing interval needs to be adjusted, and the blood concentration of this product should be followed up and monitored. 9. Angiotensin converting enzyme inhibitors and their receptor antagonists can increase the blood concentration of this product. 10. Edrophonium Chloride (Tensilon) and this product can cause obvious bradycardia. 11. Indometacin (Indometacin) can reduce the renal clearance of this product, prolonging the half-life of this product, and there is a risk of poisoning. The blood drug concentration and electrocardiogram need to be monitored. 12 When used with heparin, since this product may partially offset the anticoagulant effect of heparin, the heparin dosage needs to be adjusted. 13. Intravenous use of magnesium sulfate during digitalization should be extremely cautious, especially when calcium salts are also injected intravenously, as heart block may occur. 14. Erythromycin can increase the absorption of this product in the gastrointestinal tract by changing the gastrointestinal flora. 15. Metoclopramide (Metoclopramide, Maxolon) reduces the bioavailability of digoxin by about 25% due to promoting intestinal motility. Propane increases the bioavailability of digoxin by about 25% due to inhibiting intestinal peristalsis.

Keep tightly closed in a dry place.