Digoxin 0.25 mg/ml

Solution for injection

Indicated in the management of chronic cardiac failure, systolic dysfunction, ventricular dilatation, cardiac failure is accompanied by atrial fibrillation.
The management of certain supraventricular arrhythmias, particularly chronic atrial flutter and fibrillation.

Posology:
The dose of digoxin for each patient has to be tailored individually according to age, lean body weight and renal function.
Suggested doses are intended only as an initial guide.
In cases where cardiac glycosides have been taken in the preceding two weeks the recommendations for initial dosing of a patient should be reconsidered and a reduced dose is advised.
The difference in bioavailability between injectable digoxin and oral formulations must be considered when changing from one dosage form to another. For example if patients are switched from oral to the I.V. formulation the dosage should be reduced by approximately 33%.
Adults and paediatric populations over 10 years
Parenteral loading:
Parenteral loading should only be used in patients who have not been given cardiac glycosides within the preceding two weeks.
The total loading dose of parenteral digoxin is 500 to 1000 micrograms (0.5 to 1.0 mg) depending on age, lean body weight and renal function. The total loading dose should be administered in divided doses with approximately half of the total dose given as the first dose and further fractions of the total dose given at intervals of four to eight hours. An assessment of clinical response should be performed before giving each additional dose.
Each dose should be given by I.V. infusion (see Method of Administration, below) over 10 to 20 mins.

Elderly
The possibility of reduced renal function and lower lean body mass should be taken into account when dealing with elderly patients. If necessary, the dosage should be reduced and adjusted to the changed pharmacokinetics to prevent elevated serum dioxin levels and the risk of toxicity. The serum dioxin levels should be checked regularly and hypokalaemia should be avoided.
Renal impairment
The dosing recommendations should be reconsidered if patients are elderly or there are other reasons for the renal clearance of digoxin being reduced. A reduction in both initial and maintenance doses should be considered (see Section 4.4).
Method of administration:
Dilution of digoxin injection:
Digoxin injection can be administered undiluted or diluted with a 4-fold or greater volume of 0.9% Sodium Chloride Injection, 0.18 % Sodium Chloride/4% Glucose Injection or 5% Glucose Injection. A 4-fold volume of diluent equates to adding one 2 ml ampoule of digoxin to 6 ml of injection solution. The use of less than a 4-fold volume of diluent could lead to precipitation of digoxin.
Digoxin injection, when diluted in the ratio of 1 to 250 is known to be compatible with the following infusion solutions and stable for up to 48 h at room temperature (20 to 25 °C):
• Sodium Chloride I.V. Infusion, B.P., 0.9 % w/v.
• Sodium Chloride (0.18 % w/v) and Glucose (4 % w/v) I.V. Infusion, B.P.
• Glucose I.V. Infusion, B.P., 5 % w/v.
A ratio of 1 to 250 can be obtained for example by diluting one 2 ml ampoule with 500 ml of infusion solution.
Dilution should be carried out either under full aseptic conditions or immediately before use. Any unused solution should be discarded (see Section 6.6).
Administration of digoxin injection:
Each dose should be given by I.V. infusion over 10 to 20 mins.
The total loading dose should be administered in divided doses with approximately half of the total dose given as the first dose and further fractions of the total dose given at intervals of four to eight hours. An assessment of clinical response should be performed before giving each additional dose.
The I.M. route is painful and is associated with muscle necrosis. This route cannot be recommended.
Rapid I.V. injection can cause vasoconstriction producing hypertension and/or reduced coronary flow. A slow injection rate is therefore important in hypertensive heart failure and acute myocardial infarction.