What Is the Connection Between Digoxin and Hypokalemia?

Digoxin tablets, the indications are 1. For hypertension, valvular heart disease, congenital heart disease and other acute and chronic cardiac insufficiency. It is especially suitable for cardiac insufficiency of atrial fibrillation with rapid ventricular rate; for the heart with pulmonary heart disease, severe myocardial ischemia, active myocarditis and extracardiac factors such as severe anemia, hypothyroidism and vitamin B ₁ deficiency 1. Poor efficacy due to insufficiency; 2. Used to control atrial fibrillation with rapid ventricular rate, ventricular rate in patients with atrial flutter, and supraventricular tachycardia.

Drug Name: Digoxin tablets

Drug type: Prescription medicines, essential medicines, medicines for medical workers' injuries
Use classification: Positive inotropics

Digoxin tablets ingredients

Chemical name: 3-[[O-2,6-dideoxy--D-nuclear-hexapyranosyl- (1 4) -O-2,6-dideoxy--D-nuclear-hexane Pyranosyl- (1 4) -2,6-dideoxy--D-nucleo-hexylpyranosyl] oxo] -12, 14-dihydroxy-5-cardio-20 (22) Enone.
Chemical Structure:

Molecular formula: C ₄₁ H ₆₄ O ₁₄
Molecular weight: 780.95

Digoxin Tablet Properties

This product is a white tablet.

Digoxin tablets indications

1. For hypertension, valvular heart disease, congenital heart disease and other acute and chronic cardiac insufficiency. It is especially suitable for cardiac insufficiency of atrial fibrillation with rapid ventricular rate; for the heart with pulmonary heart disease, severe myocardial ischemia, active myocarditis and extracardiac factors such as severe anemia, hypothyroidism and vitamin B ₁ deficiency Insufficiency of poor function;
2. Used to control atrial fibrillation with rapid ventricular rate, ventricular rate in patients with atrial flutter, and supraventricular tachycardia.

Digoxin tablets specifications

0.25mg

Digoxin tablets dosage

Usual amount for adults, orally:

Commonly used 0.125 0.5mg (that is, 0.5 tablets 2 tablets), once a day, can reach the steady-state blood drug concentration in 7 days; if the fast load is reached, 0.25mg (1 tablet) can be administered every 6-8 hours, the total Dose of 0.75 to 1.25 mg / day (3 to 5 tablets per day): maintenance amount, 0.125 to 0.5 mg once daily (0.5 to 2 tablets each time).

Commonly used in children, orally:

The total amount of this product is 0.02 ~ 0.03mg / kg for premature infants; 0.03 ~ 0.04mg / kg for neonates under 1 month: January ~ 2 years old, 0.05 ~ 0.06mg / kg; 2 ~ 5 years old, 0.03 ~ 0.04mg / kg kg; 5 to 10 years old, 0.02 to 0.035 mg / kg; 10 years old or older, according to the usual dosage for adults: the total amount of this product is divided into 3 times or every 6 to 8 hours. The maintenance amount 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) need to titrate the dose carefully and closely monitor blood concentration and electrocardiogram. In recent years, it has been proved through research that digoxin is given a certain daily dose, and can reach a stable concentration in the body after 6 to 7 days to exert its full effect. Therefore, those who are not in a hurry and are susceptible to poisoning can use 5.5 g / kg daily. Administration can also obtain satisfactory therapeutic effects and reduce the incidence of poisoning.

Digoxin tablets adverse reactions

1. Common adverse reactions include: arrhythmia, poor appetite or nausea, vomiting (stimulation of the medulla oblongata), lower abdominal pain, abnormal weakness, and weakness.
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: lethargy, headaches and rashes, and measles (allergic reactions).
4 Among the manifestations of digitalis poisoning, arrhythmia is the most important, and the most common is ventricular premature beats, which accounts for about 33% of the adverse reactions to arrhythmia. Followed by atrioventricular block, paroxysmal or accelerated border tachycardia, paroxysmal atrial tachycardia with atrioventricular block, ventricular tachycardia, sinus arrest, ventricular fibrillation, etc. Central arrhythmias are more common in children than in other reactions, but ventricular arrhythmias are less common than in adults. Newborns may have prolonged PR intervals.

Digoxin tablets taboo

Combined with calcium injection; poisoning with any digitalis preparation; ventricular tachycardia, ventricular fibrillation; obstructive hypertrophic cardiomyopathy (can still be considered if with systolic insufficiency or atrial fibrillation); preexcitation syndrome with atrial fibrillation or flutter move.

Digoxin tablets precautions

1. Not compatible with acids and bases.
2. Use with caution: hypokalemia; incomplete atrioventricular block; hypercalcemia; hypothyroidism; ischemic heart disease; myocardial infarction; myocarditis; impaired renal function.
3 Follow-up inspections should be taken during medication: blood pressure, heart rate and heart rhythm; electrocardiogram; cardiac function monitoring; electrolytes especially potassium, calcium, magnesium; renal function; digoxin blood concentration should be determined when digitalis poisoning is suspected. When overdose, due to the small accumulation,-the symptoms of poisoning usually disappear 1 to 2 days after stopping the drug.
4 Pay attention to monitoring the blood concentration of digoxin during application.
5. The dosage of this product should be individualized.

Digoxin tablets for pregnant and lactating women

This product can pass through the placenta, so the maternal dosage may increase in the third trimester, and it should be reduced 6 weeks after delivery. This product can be excreted into breast milk. The application of breastfeeding women must be weighed against the pros and cons.

Digoxin tablets for children

Neonatal tolerance to this product is uncertain, and its renal clearance is reduced; premature and immature infants are sensitive to this product, and the dose is reduced according to its immaturity. According to body weight or body surface area, infants over 1 month are slightly larger than adults.

Digoxin tablets for the elderly

Elderly patients with liver and kidney dysfunction, reduced apparent volume of distribution, or electrolyte imbalance, have low tolerance to this product and must reduce the dose.

Digoxin tablets drug interactions

1. When used with amphotericin B, corticosteroids or potassium-deficient diuretics, such as Bumetanide (butanuramine) and Ethacrynic Acid (diuretic acid), it can cause hypokalemia and cause ocean Rehmannia poisoning.
2. With antacids (especially magnesium trisilicate) or antidiarrheal adsorbents such as white clay, pectin, colestyramine (cholestyramine) and other anion exchange resins, sulfasalazine or neomycete When used in combination with paracetamol and p-salicylic acid, it can inhibit the absorption of digitalis and cardiac glycosides, resulting in a weakened effect of cardiac glycosides.
3 With antiarrhythmics, calcium injections, cocaine, pancuronium bromide (Pancoron, Pawrowang), rapamine, succinylcholine (Scoline; Suxamethonium Chloride) or epinephrine When the drugs are used together, arrhythmia can be caused by the additive effects.
4 Patients with severe or complete atrioventricular block with normal potassium should not use potassium salts at the same time. However, when thiazide diuretics are used together with this product, potassium salts must be given to prevent hypokalemia. Bloodemia.
5. Beta blockers used with this product may cause severe bradycardia in atrioventricular block, which should be taken seriously. However, it is not ruled out that -blockers are used for digital ventricular tachyarrhythmias that cannot control ventricular rate.
6. With the use of quinidine, the blood concentration of this product can be doubled. The increase is related to the amount of quinidine. It can even reach the toxic concentration. Even if digoxin is stopped, its blood concentration will continue to rise. It is because quinidine replaced digoxin from the tissue junction to reduce its distribution volume. The dosage of digoxin should be reduced by 1/2 to 1/3 when the two drugs are combined.
7. Combined with verapamil, diltiazem, and amiodarone, due to lowering the clearance of digoxin from the kidney and the whole body and increasing its blood concentration, it can cause severe bradycardia.
8. Spironolactone can prolong the half-life of this product, you need to adjust the dose or the interval between administrations, and follow-up monitoring the blood concentration of this product.
9. Angiotensin-converting enzyme inhibitor and its receptor antagonist can increase the blood concentration of this product.
10 Edrophonium Chloride (Tensilon) combined with this product can cause significant bradycardia.
11. Indometacin (Indomethacin) can reduce the renal clearance of this product, prolong the half-life of this product, and is at risk of poisoning. Monitor blood concentration and electrocardiogram.
12. Used with heparin, as this product may partially offset the anticoagulant effect of heparin, the amount of heparin needs to be adjusted.
13. In the case of digitalis, intravenous magnesium sulfate should be used with extreme caution, especially when calcium salts are also given intravenously, cardiac blockade can occur.
14. Erythromycin can increase the absorption of this product in the gastrointestinal tract due to changes in the gastrointestinal flora.
15. Metoclopramide (Metoclopramide, Maxolon) has reduced the bioavailability of digoxin by about 25% because it promotes bowel movements. Probencin improves the bioavailability of digoxin by inhibiting intestinal peristalsis by about 25%.

Digoxin tablets overdose

1. If the blood concentration of digoxin is 2.0 ~ 2.5ng / ml, the digoxin drug should be alert for overdose or toxic reaction.
2. Patients have taken any digitalis preparations 2 to 3 weeks ago, and should be given in small doses to avoid poisoning.
3 Cardiac glycoside dose calculation should be based on standard body weight, because adipose tissue does not take up cardioside.
4 The recommended dose is only an average dose, and each dose must be adjusted according to the needs of the patient.
5. For patients with liver dysfunction, digitalis preparations that do not focus on liver metabolism should be selected.
6. Digitalis is used in patients with renal insufficiency, because most of the metabolites excreted in urine are inactive and do not affect the half-life of this product.
7. Digitalis patients are extremely sensitive to cardioversion and should be highly vigilant.
8. Dialysis cannot remove this product quickly from the body.
9. When this product causes severe or complete atrioventricular block, potassium supplementation is not recommended.
10 Renal insufficiency, the elderly and the weak can have poisoning reactions at the usual dose and blood concentration. Infants and young children, especially premature and stunted infants, should adjust the dose under the blood drug concentration and ECG monitoring.
11. When the patient changed from cardiac glycoside injection to this product, the dose needs to be adjusted in order to compensate for the pharmacokinetic differences between drugs.
12. It should be administered intravenously because intramuscular injection has a marked local response, and has a slow effect and poor bioavailability.
13. Treatment of this product overdose and toxic reaction: Those with mild poisoning should stop using this product and diuretic treatment. If there is hypokalemia and renal function is good, potassium salt can be given. Available for those with arrhythmia:
(1) Intravenous infusion of potassium chloride is often effective in eliminating ectopic rhythms.
(2) Sodium phenytoin, which can compete with cardiac glycosides for Na ⁺ -K ⁺ -ATPase, and thus has a detoxifying effect. For adults, take a slow intravenous injection of 100-200mg plus 20ml of water for injection. If the situation is not urgent, it can be taken orally, 0.1mg each time, 3 to 4 times a day.
(3) Lidocaine is effective in eliminating ventricular arrhythmias. Adults use 50 to 100 mg of glucose injection intravenously, which can be repeated if necessary.
(4) Atropine is available for those with bradycardia. Adults use 0.5 to 2 mg subcutaneously or intravenously.
(5) Temporary pacemaker can be implanted when bradycardia or complete atrioventricular block may cause Asthma Syndrome. Application of isoproterenol can increase slow heart rate.
(6) Calcium Disodium Edetate, with its chelation effect on calcium, can also be used to treat arrhythmias caused by digitalis.
(7) Digoxin-immunized Fab fragments can be administered intravenously through membrane filters to potentially life-threatening digitalis poisoning. Each 40 g of digoxin-immunized Fab fragments binds approximately 0.6 g of digoxin or digoxigenin.

Digoxin tablets pharmacology and toxicology

At the therapeutic dose Positive inotropic effect: This product selectively binds to the Na + -K + ATP enzyme of the cardiac cell membrane and inhibits the enzyme activity, which impairs the active coupling and transport of Na ⁺ -K ⁺ inside and outside the myocardial cell membrane, and increases the Na ⁺ concentration in the cardiac cell High, so that the Na + -Ca ²⁺ exchange on the sarcolemma becomes active, Ca + 2 in the cytoplasm increases, Ca ²⁺ storage in the sarcoplasmic network increases, and more Ca ^{2+ is} released when the myocardium is excited; Increased Ca ²⁺ concentration in myocardial cells excites myocardial contractile proteins and increases myocardial contractility.
2. Negative frequency effect: Due to its positive inotropic effect, the cardiac output of the failing heart is increased, the hemodynamic state is improved, the reflexivity of eliminating sympathetic nerve tension is increased, and the vagus nerve tension is increased, thereby slowing the heart rate. In addition, increasing the sensitivity of the sinoatrial node to vagus nerve impulses at low doses can enhance its heart rate slowing effect. Large doses (usually close to the amount of poisoning) can directly inhibit the sinoatrial node, atrioventricular node, and the His bundle and show sinus bradycardia and atrioventricular block of varying degrees.
3 Cardiac electrophysiological effects: through direct effects on myocardial electrical activity and indirect effects on vagus nerves, reduce sinus node self-discipline; improve Purkinje fiber self-discipline; slow atrioventricular node conduction velocity and extend its effective refractory period , Leading to increased atrioventricular node occult conduction, which can slow the ventricular rate of atrial fibrillation or atrial flutter; because this drug shortens the effective refractory period of atrial, when used in atrial tachycardia and atrial flutter, it may lead to atrial Accelerated rate and atrial flutter turned into atrial fibrillation; shortened effective refractory period of Purkinje fibers.

Pharmacokinetics of Digoxin Tablets

This product is cardiac glycoside, which is purified from foxglove digitalis, and is characterized by faster excretion and less accumulation. Oral absorption is mainly through the upper small intestine, absorption is incomplete and irregular, oral absorption rate is about 75%, bioavailability: 60% to 80% for tablets, oral onset time 0.5 to 2 hours, and plasma concentration peak time 2 ~ 3 hours, the maximum effect time is 4 ~ 6 hours. Digoxin elimination half-life averaged 36 hours. Distribution: It is widely distributed to various tissues after absorption, and partly absorbed into the blood through the biliary tract, forming the liver-gut circulation. The plasma protein binding rate is low, 20% to 25%, and the apparent volume of distribution is 6 to 10L / kg. Metabolism and excretion: Digoxin is rarely transformed and metabolized in the body, and is mainly eliminated by the kidneys in the original form. The urine excretion is 50% to 70% of the amount.

Digoxin tablets storage

Keep sealed.

Digoxin tablets packaging

Oral solid medicinal high-density polyethylene bottle, 100 tablets / bottle.

Digoxin tablets expiration date

36 months.

Digoxin film implementation standards

"Chinese Pharmacopoeia" 2010 edition two. ^[1]