Uses of Myoxin: - Heart failure - Arrhythmia Heart failure, Supraventricular arrhythmias, Atrial fibrillation and Atrial flutter Digitalis toxicity, ventricular tachycardia/fibrillation, obstructive cardiomyopathy. Arrhythmias due to accessory pathways (e.g. Wolff-Parkinson-White syndrome).

Positive Inotropic drugs

Digoxin is a cardiac glycoside used in the management of particularly atrial fibrillation and in heart failure. The principal actions of digoxin are an increase in the force of myocardial contraction (positive inotropic activity) and a reduction in the conductivity of the heart particularly in conduction through the atrioventricular (AV) +node. Digoxin also has a direct action on vascular smooth muscle and indirect effects mediated primarily by the autonomic nervous system and particularly by an increase in the vagal activity.

How to use Digoxin: Take this medicine in the dose and duration as advised by your doctor. Swallow it as a whole. Do not chew, crush or break it. Digoxin may be taken with or without food, but it is better to take it at a fixed time. Administration: May be taken with or without food. Adult Dose: Atrial Fibrillation Rapid digitalizing (loading-dose) regimen PO: 10-15 mcg/kg total loading dose; administer 50% initially; then may cautiously give 1/4 the loading dose q6-8hr twice; peform careful assessment of clinical response and toxicity before each dose Maintenance PO: 3.4-5.1 mcg/kg/day or 0.125-0.5 mg/day PO; may increase dose every 2 weeks based on clinical response, serum drug levels, and toxicity Heart Failure As per ACCF/AHA guidelines, a loading dose to initiate digoxin therapy in patients with heart failure is not necessary 0.125-0.25 mg PO/IV qDay; higher doses including 0.375-0.5 mg/day rarely needed Use lower end of dosing (0.125 mg/day) in patients with low lean body mass Child Dose: Heart Failure/Atrial Fibrillation Use doses at the lower end of the spectrm when treating heart failure Reduce dose by 20-25% when changing from oral formulation or IM to IV therapy Premature neonate PO: 1st loading dose, 10-15 mcg/kg; 2nd and 3rd loading doses, 5-7.5 mcg/kg q6-8hr for 2 doses; maintenance: 5-7.5 mcg/kg/day divided q12hr Full-term neonate PO: 1st loading dose, 12.5-17.5 mcg/kg; 2nd and 3rd loading doses, 6.25-8.75 mcg/kg q6-8hr for 2 doses; maintenance: 6-10 mcg/kg/day divided q12hr Infants & children 1-24 months PO: 1st loading dose, 17.5-30 mcg/kg; 2nd and 3rd loading doses, 8.75-15 mcg/kg q6-8hr for 2 doses; maintenance: 10-15 mcg/kg/day divided q12hr 2-5 years PO: 1st loading dose, 15-20 mcg/kg; 2nd and 3rd loading doses, 8.75-10 mcg/kg q6-8hr for 2 doses; maintenance: 7.5-10 mcg/kg/day divided q12hr 5-10 years PO: 1st loading dose, 10-17.5 mcg/kg; 2nd and 3rd loading doses, 5-8.75 mcg/kg q6-8hr for 2 doses; maintenance: 5-10 mcg/kg/day divided q12hr >10 years & <100 kg PO: 1st loading dose, 5-7.5 mcg/kg; 2nd and 3rd loading doses, 2.5-3.75 mcg/kg q6-8hr for 2 doses; maintenance: 2.5-5 mcg/kg/day Renal Dose: Use lower end of dosing (0.125 mg/day) in patients with impaired renal function

Effectiveness reduced by phenytoin, neomycin, sulphasalazine, kaolin, pectin, antacids and in patients receiving radiotherapy. Metoclopramide may alter the absorption of solid dosage forms of digoxin. Blood levels increased by calcium channel blockers, spironolactone, quinidine and calcium salts. Potentially Fatal: Electrolyte imbalances such as hypokalaemia and hypomagnesemia (e.g. admin of potassium-losing diuretics, corticosteroids) can increase the risk of cardiac toxicity.

Digitalis toxicity, ventricular tachycardia/fibrillation, obstructive cardiomyopathy. Arrhythmias due to accessory pathways (e.g. Wolff-Parkinson-White syndrome).

Common - Visual impairment - Skin rash - Nausea - Vomiting - Diarrhea - Dizziness - Arrhythmia (irregular heartbeats) 1-10% Dizziness (4.9%),Mental disturbances (4.1%),Diarrhea (3.2%),Headache (3.2%),Nausea (3.2%),Vomiting (1.6%),Maculopapular rash (1.6%) <1% Anorexia,Cardiac dysrhythmia,Arrhythmia in children (consider a toxicity) Frequency Not Defined Visual disturbance (blurred or yellow vision),Heart block (1°/2°/3°),Asystole,Tachycardia Potentially Fatal: Cardiac arrhythmias in combination with heart block.

Use in pregnancy: Digoxin can be used.Use in lactation: Digoxin is excreted in breast milk but in concentration below those found in plasma and therefore poses no hazard to the breast-feed infant.

Precaution: Cardiac dysrhythmias, hypokalaemia, hypertension, IHD, hypercalcaemia, hypomagnesaemia, electroconversion, chronic cor pulmonale, aortic valve disease, acute myocarditis, congestive cardiomyopathies, constrictive pericarditis, heart block, elderly, renal impairment, abnormalities in thyroid function; pregnancy. IV digoxin can only be given to patients who have not received cardiac glycosides in the preceding 2 wk. Lactation: Drug enters breast milk; use with caution (American Academy of Pediatrics committee states, "compatible with nursing")

Symptoms: Hyperkalaemia, cardiac arrhythmias and heart block. Management: Treatment is symptomatic and supportive. Reduce absorption by gastric lavage if present within 30 min of ingestion. Do not induce vomiting or attempt passage of a gastric tube if presented >2 hr after ingestion or already has toxic manifestations, as this may induce an acute vagal episode and worsen digitalis-related arrhythmias. Activated charcoal is helpful in reducing drug absorption.

Store in a cool and dry place.Keep out of the reach of children.

Positive Inotropic drugs

Digoxin is a cardiac glycoside which has positive inotropic activity characterized by an increase in the force of myocardial contraction. It also reduces the conductivity of the heart through the atrioventricular (AV) node. Digoxin also exerts direct action on vascular smooth muscle and indirect effects mediated primarily by the autonomic nervous system and an increase in vagal activity.

Pregnancy Experience with digoxin in pregnant women over several decades, based on published retrospective clinical studies and case reports, has not led to the identification of a drug associated risk of major birth defects, miscarriage or adverse maternal and fetal outcomes Untreated underlying maternal conditions (eg, heart failure, atrial fibrillation) during pregnancy pose a risk to the mother and fetus Clinical considerations Pregnant women with heart failure are at increased risk for preterm birth; clinical classification of heart disease may worsen with pregnancy and lead to maternal or fetal death Pregnant women with atrial fibrillation are at an increased risk of delivering a low birth weight infant; atrial fibrillation may worsen with pregnancy and can lead to maternal or fetal death Fetal/neonatal adverse reactions Digoxin has been shown to cross the placenta and is found in amniotic fluid Monitor neonates for signs and symptoms of digoxin toxicity, including vomiting, and cardiac arrhythmias Dose adjustments during pregnancy and the postpartum period Digoxin requirements may increase during pregnancy and decrease in the postpartum period Monitor serum digoxin levels during pregnancy and the postpartum period Labor or delivery Risk of arrhythmias may increase during labor and delivery Monitor patients continuously during labor and delivery Lactation The digoxin dose received through breastfeeding is up to 4% of the neonatal maintenance dosage, which is unlikely to be clinically relevant There are no data on the effects of digoxin on the breastfed infant or the effects on milk production