Posology : מינונים

4.2 Posology and method of administration

Posology

Local and regional anaesthesia
As a matter of principle the smallest possible dose that produces adequate anaesthesia should be administered. The dosage should be adjusted individually according to the particulars of each case.


Adults:
When injected into tissues with marked systemic absorption, without combination with a vasoconstrictor, a single dose of lidocaine hydrochloride monohydrate should not exceed 4.5 mg/kg body weight (BW) (or 300 mg). If combined with a vasoconstrictor, 7 mg/kg BW (or 500 mg) of lidocaine hydrochloride monohydrate per single dose should not be exceeded.



Type of anaesthesia                      Concentration [%]          Usual volume [ml] Maximum dose [mg] Infiltration                             0.5-1                                        300 500 (with epinephrine)
Major nerve blocks                       1-2                        30-50             500 (with epinephrine) Minor nerve blocks                        1                        5-20                 200 Epidural                                  1-2                      15-30*               500 (with epinephrine) Spinal                                    1.5 or 5 in 7.5% glucose 1-2                  100 Intravenous regional anaesthesia (IVRA)
-upper limb                               0.5                      40 -lower limb                               0.25                     50-100 *1.5 ml per segment in average
For prolongation of anaesthesia lidocaine may be combined with a vasoconstrictor, e.g. epinephrine. Addition of epinephrine at a concentration of 1:100 000 to 1:200 000 has proven useful.

Paediatric population
For children, the doses are calculated individually according to the patients' age body weight and the nature of the procedure. Up to 5mg/kg BW may be administered. With the addition of epinephrine, up to 7 mg/kg can be used. In children with a high body weight a gradual reduction of the dosage is often necessary and should be based on the ideal body weight. Standard textbooks should be consulted for factors affecting specific block techniques and for individual patient requirements. For anaesthesia in children, only a low strength (0.5 % w/v) of the local anaesthetic should be used. To achieve a complete motor block, a higher strength (1 % w/v) may be required.
Lidocaine should be used with caution in children younger than two years of age as there are limited data to support the safety and efficacy of this product in this patient population at this time.

Elderly patients
For elderly patients, the doses must be calculated individually according to the patients' age and body weight.
Dosages may need adaptation as cardiac output and hepatic blood flow may decrease with advanced age indicating a decreased clearance of lidocaine (see section 5.2).

Other special patient groups
- Doses should be reduced in patients in poor general condition or in those with reduced protein binding capacity (resulting e.g. from renal insufficiency, liver insufficiency, cancer, pregnancy).
-In patients with severe renal insufficiency the dose may need to be adapted due to reduced clearance and increased half-life of lidocaine (see section 5.2). Patients with liver diseases show reduced tolerance towards amide-type local anaesthetics. This may be due to reduced hepatic metabolism and decreased protein synthesis resulting in a lower protein binding rate of the local anaesthetic. Dose reduction is advisable in such cases.
-The dose should be reduced in patients showing clinical signs of cardiac insufficiency. Nevertheless, local or regional nerve blockage can be the anaesthetic method of choice in such patients.
-During pregnancy, the dose may need to be reduced depending on the type of anaesthesia. Regional anaesthetic blocks in which usually large doses are required should be avoided during the first trimester. For use in anaesthetic blocks in which smaller doses are administered the dosage may need to be reduced because of the altered anatomical and physiological characteristics in late pregnancy.

Antiarrhythmic therapy
Adults
The dosage must be adjusted according to individual requirements and the therapeutic effect.

Bolus:
Usual loading doses are 50-100 mg or 1 - 1.5 mg/kg BW of lidocaine hydrochloride monohydrate as direct intravenous injection, corresponding to approximately 2.5 - 5 ml or 0.05 - 0.075 ml/kg BW of 2% w/v lidocaine hydrochloride injection. The rate of injection should not exceed 25-50 mg/min, corresponding to approximately 1.25 - 2.5 ml/min 2% w/v lidocaine hydrochloride injection.
If the therapeutic effect of the first dose is insufficient within the first 5 - 10 minutes, the initial dose may be 

repeated once or twice up to a maximum dose of 200 - 300 mg in 1 hour.
Maintenance:
To maintain therapeutic plasma lidocaine concentrations (1.5 - 5 microgram/ml), lidocaine hydrochloride monohydrate is infused at a rate of 20 - 50 microgram/kg BW/min (about 1-4 mg/min), corresponding to approximately 0.001 - 0.0025 ml /kg BW/min.
Infusions can be prepared by adding 1000 mg of lidocaine hydrochloride monohydrate, corresponding to 50 ml 2% w/v lidocaine hydrochloride Injection, to 500 ml of glucose solution or physiological saline.
The infusion should be terminated as soon as the patient's basic cardiac rhythm appears to be stable or at the earliest signs of toxicity. It should rarely be necessary to continue the infusion beyond 24 hours. As soon as possible, patients should be changed to an oral antiarrhythmic agent for maintenance therapy.

Paediatric patients
The safety and the efficacy of the use of lidocaine in children have not yet been definitely established. The dose should be adapted according to the clinical situation and the nature of the procedure.
Infants and children may be given an initial iv bolus of 0.5- 1 mg/kg BW. This dose may be repeated according to the response of the patient, but the total dose should not exceed 3-5 mg/kg BW. If required, a maintenance i.v. infusion of 10 - 50 microgram/kg BW/min may be given via an infusion pump.
For advanced cardiovascular life support in children, the recommended dosage is an initial rapid i.v. or intraosseous injection (i.e. bolus) of 1 mg/kg BW up to a maximum initial dose of 100 mg.
If ventricular tachycardia or ventricular fibrillation is not corrected following defibrillation (or cardioversion) and an initial recommended dose of lidocaine, an i.v. or intraosseous infusion should be started at a rate of 20-50 microgram/kg BW per min.

Elderly patients
For elderly patients, the doses are calculated individually according to the patients' age and body weight.
Dosages may need adaptation as cardiac output and hepatic blood flow decrease with advanced age indicating a decreased clearance of lidocaine (see section 5.2).

Other special patient groups
Cardiac insufficiency, hepatic insufficiency, co-medication, pregnancy The dose should be reduced in patients with cardiac insufficiency, hepatic insufficiency, in patients receiving drugs that intensify the effects of lidocaine (see section 4.5) and during pregnancy (see section 4.6). See also section 5.2.
Renal insufficiency
Renal insufficiency as a rule does not require specific dose adjustment. However, such patients should be monitored for toxic effects caused by accumulation of active metabolites.
In cases of severe renal insufficiency the dose may need to be adapted (see also section 5.2).

Method of administration

Local and regional anaesthesia
Intradermal, intramuscular, subcutaneous, submucosal use (infiltration), injection into the surroundings of peripheral nerves (perineural), epidural or spinal use. Intravenous use regarding intravenous regional anaesthesia (Bier's block).
Every local anaesthetic procedure should only be carried out by personnel adequately skilled in the respective anaesthetic technique.

Antiarrhythmic therapy
Intravenous use
Administer as slow intravenous injection or intravenous infusion after dilution in a suitable vehicle solution.
Because of the relatively short duration of action of lidocaine, the injection should be followed by continuous infusion, if possible, using an infusion pump.