XYLOCARD Solution for injection Ref.[27837] Active ingredients: Lidocaine

3.1 Dosing Considerations

• The onset of action following a single intravenous injection varies from 45 to 90 seconds. Duration of action is 10 to 20 minutes.
• No more than 200 to 300 mg of XYLOCARD should be administered during a one-hour period (see WARNINGS AND PRECAUTIONS – General, Pharmacodynamics, and General Toxicology).
• Intravenous infusions should be terminated as soon as the patient’s basic cardiac rhythm appears to be stable or at the earliest signs of toxicity. It is rarely necessary to continue intravenous infusion beyond 24 hours. As soon as possible, and when indicated, patients should be changed to an oral antiarrhythmic agent for maintenance therapy.
• Intravenous infusions of XYLOCARD must be administered under constant ECG and blood pressure monitoring and with meticulous regulation of infusion rate, in order to avoid potential overdosage and toxicity.

3.2 Recommended Dose and Dosage Adjustment

Single Intravenous Injection

The usual dose is 50 to 100 mg XYLOCARD (lidocaine hydrochloride) administered under ECG and blood pressure monitoring. This dose may be administered at the rate of approximately 25 to 50 mg/min. Sufficient time should be allowed to enable a slow circulation to carry the drug to the site of action. If the initial injection of 50 to 100 mg does not produce a desired response, a second dose may be repeated after 10 minutes. Elderly patients and those with congestive heart failure or cardiogenic shock may require smaller bolus doses.

Continuous Intravenous Infusion

Following intravenous injection, XYLOCARD may be administered by intravenous infusion at a rate of 1-2 mg/min (approximately 15-30 µg/kg/min in the average 70 kg patient) in those patients in whom the arrhythmia tends to recur, and who are incapable of receiving oral antiarrhythmic therapy.

Health Canada has not authorized an indication for pediatric use.

3.3 Administration

XYLOCARD is for intravenous administration (injection, infusion) only.

In the treatment of ventricular arrhythmias, an intravenous injection should be given initially, followed by an intravenous infusion.

Continuous infusion: XYLOCARD should be diluted to the desired concentration in an appropriate infusion solution using aseptic technique (see Reconstitution).

When administering XYLOCARD, careful and constant monitoring of cardiovascular and respiratory vital signs and the patient’s state of consciousness is required. At the first sign of change, oxygen should be administered.

3.4 Reconstitution

Table 1. Reconstitution:

5% dextrose in water is the preferred diluent for continuous intravenous infusion.

Solution for intravenous infusion may be prepared by adding one gram of XYLOCARD (i.e., contents of ten 5 mL ampoules) to one litre of an appropriate infusion solution. Approximately a 0.1% solution will result from this procedure; that is, each mL will contain approximately 1 mg of XYLOCARD.

In those cases in which fluid restriction is medically desirable, a more concentrated solution may be prepared by adding one gram of XYLOCARD (i.e., contents of ten 5 mL ampoules) to 500 mL of diluent. Approximately a 0.2% solution will result from this procedure; that is, each mL will contain approximately 2 mg of XYLOCARD.

Solutions should be prepared using aseptic technique. As with all intravenous admixtures, dilution should be made just prior to administration. Prepared solutions should be used within 12 hours (see STORAGE, STABILITY AND DISPOSAL).

Symptoms of idiosyncratic reactions are described under ADVERSE REACTIONS.

Toxicity is initially manifested as CNS excitation and may result in a slow onset of nervousness, dizziness, delirium, blurred vision and tremors followed by drowsiness, convulsions, unconsciousness and possibly respiratory arrest.

Cardiovascular toxic effects are generally preceded by signs of toxicity in the central nervous system, unless the patient is receiving a general anaesthetic or is heavily sedated with medicines such as a benzodiazepine or a barbiturate. Toxic cardiovascular reactions are usually depressant in nature, may occur rapidly and with little warning and can lead to peripheral vasodilation, severe hypotension, conduction defects, bradycardia, asystole, arrhythmias, including ventricular tachycardia/fibrillation, cardiovascular collapse which may lead, to cardiac arrest, apnea, seizures, coma, respiratory arrest and death. In rare cases, cardiac arrest has occurred without prodromal CNS effects.

Treatment of Overdose

Discontinue administration of XYLOCARD. Maintain a patent airway and support ventilation with oxygen and assisted or controlled respiration as required. Should a convulsion persist despite ventilation therapy, small increments of a benzodiazepine (e.g. diazepam) or an ultrashort-acting barbiturate (e.g. thiopentone) may be given intravenously, bearing in mind that anticonvulsant drugs may also depress respiration and the circulation. Use of intravenous lipid emulsion should be considered.

Cardiovascular depression may require circulatory assistance in the form of elevation of legs, intravenous fluids and/or vasopressor agents, volume expanders and, if necessary, cardiac massage.

Lidocaine toxicity may appear at serum concentrations greater than 8 mg/L. Central nervous system toxicity is a graded response, with symptoms and signs of escalating severity. The first symptoms are circumoral paresthesia, numbness of the tongue, lightheadedness, hyperacusis and tinnitus. Visual disturbance and muscular tremors are more serious and precede the onset of generalized convulsions.

Unconsciousness and grand mal convulsions may follow, which may last from a few seconds to several minutes. Hypoxia and hypercarbia occur rapidly following convulsions due to the increased muscular activity, together with the interference with normal respiration. In severe cases apnea may occur.

Acidosis increases the toxic effects.

Recovery is due to redistribution and metabolism of the drug. Recovery may be rapid unless large amounts of the drug (>5 µg/mL) have been administered.

If the convulsions do not stop spontaneously in 15-20 seconds, an anticonvulsant should be given intravenously. Intravenous administration of thiopental 100-150 mg will abort the convulsions rapidly. Alternatively, diazepam 5-10 mg i.v. may be used, although its action is slower.

Hypotension may be counteracted by giving sympathomimetic drugs (e.g., epinephrine). Adrenergic agents of both α-adrenoceptor stimulating and β-adrenoceptor stimulating type are generally effective. The bradycardia may be treated with parasympatholytic agents.

Should circulatory arrest occur, immediate cardiopulmonary resuscitation should be instituted. Continued optimal oxygenation and ventilation and circulatory support as well as treatment of acidosis are of vital importance, since hypoxia and acidosis will increase the systemic toxicity of local anesthetics.

For management of a suspected drug overdose, contact your regional poison control centre.

Store at room temperature (15-25°C).

XYLOCARD solutions are preservative free and are for single use. Discard unused portion after a maximum of 12 hours.