Life-threatening ventricular arrhythmias, arrhythmias secondary to digitalis intoxication

Dosage 3.5 mg/kg to 5 mg/kg of bodyweight intravenously initially, repeated once if necessary. The solution should be injected slowly, intravenously and at a uniform rate which should not exceed 1 ml (50 mg) per minute.

Parenteral drug products should be inspected visually for particulate matter and discolouration prior to administration, whenever solution and container permit. Parenteral Epanutin is suitable for use as long as it remains free of haziness and precipitate. Upon refrigeration or freezing a precipitate might form; this will dissolve again after the solution is allowed to stand at room temperature. The product is still suitable for use. Only a clear solution should be used. A faint yellow colouration may develop, however, this has no effect on the potency of this solution.

There is a relatively small margin between full therapeutic effect and minimally toxic doses of this drug. Optimum control without clinical signs of toxicity occurs most often with serum levels between 10 mcg/mL and 20 mcg/mL (40-80 micromoles/l).

Because of the risk of local toxicity, intravenous phenytoin should be injected slowly directly into a large vein through a large-gauge needle or intravenous catheter.

Each injection or infusion of intravenous Epanutin should be preceded and followed by an injection of sterile saline through the same needle or catheter to avoid local venous irritation due to alkalinity of the solution (see section 4.4. Local Toxicity (including Purple Glove Syndrome)).

For infusion administration the parenteral phenytoin should be diluted in 50 ml-100 ml of normal saline, with the final concentration of phenytoin in the solution not exceeding 10 mg/ml. Administration should commence immediately after the mixture has been prepared and must be completed within one hour (the infusion mixture should not be refrigerated). An in-line filter (0.22 microns-0.50 microns) should be used.

The diluted form is suitable for use as long as it remains free of haziness and precipitate.

Parenteral Epanutin should neither be mixed with other drugs nor be added to dextrose or dextrose-containing solutions due to the potential for precipitation of phenytoin acid.

Continuous monitoring of the electrocardiogram and blood pressure is essential. Cardiac resuscitative equipment should be available. The patient should be observed for signs of respiratory depression. If administration of intravenous Epanutin does not terminate seizures, the use of other measures, including general anaesthesia, should be considered.