Lidocaine Hydrochloride

Pharmacology and toxicology

When the plasma concentration exceeds 5 μg·mL-1, convulsions can occur, and at low doses, it can promote the outflow of K+ in myocardial cells, reduce the auto-discipline of the myocardium, and have anti-ventricular arrhythmic effect; At therapeutic doses, there is no significant effect on the electrical activity of cardiomyocytes, atrioventricular conduction and contraction of myocardium; Further increase in blood concentration can cause slowing of cardiac conduction velocity, atrioventricular block, inhibition of myocardial contractility and decrease of cardiac output.

Pharmacokinetics

After injection, the tissue distribution is fast and widespread, and it can penetrate the blood-brain barrier and placenta. The product has high anesthesia intensity, fast onset and strong diffusion power, and it takes about 2 hours for the drug to be eliminated from the local area, and the addition of epinephrine can prolong its action time. Most of them are first degraded by liver microgranase into the deethyl intermediate metabolite monoethylglycinamide xylene that still has local anesthetic effect, the toxicity is increased, and then hydrolyzed by amidase, excreted in urine, about 10% of the dosage is excreted in the original form, and a small amount appears in bile.

Indications

The product is a local anesthetic and antiarrhythmic drug. It is mainly used for infiltration anesthesia, epidural anesthesia, surface anesthesia (including mucosal anesthesia in thoracoscopy or abdominal surgery) and nerve block. The product can be used for ventricular premature beats and ventricular tachycardia after acute myocardial infarction, and can also be used for digitalis poisoning, cardiac surgery and ventricular arrhythmias caused by cardiac catheterization, and the product is usually ineffective for supraventricular arrhythmias.

Usage and dosage

For anesthesia

1. Commonly used amount for adults

(1) Surface anesthesia: 2%-4% solution does not exceed 100mg at a time. The amount of injection administration should not exceed 4.5 mg/kg (without epinephrine) or 7 mg/kg per 7 mg/kg (with 1:200,000 concentration of epinephrine).

(2) Sacral block for labor analgesia: with 1.0% solution, limited to 200mg.

(3) Epidural block: 1.5%-2.0% solution for the thoracolumbar segment, 250-300mg.

(4) Infiltration anesthesia or intravenous area blockade: with 0.25%-0.5% solution, 50-300mg.

(5) Peripheral nerve block: brachial plexus (unilateral) with 1.5% solution, 250-300mg; 2% solution for dentistry, 20-100 mg; Intercostal nerve (each branch) with 1% solution, 30mg, 300mg as the limit; 0.5%-1.0% solution for paracervical infiltration, 100mg on the left and right sides; Paravertebral spinal nerve block (per branch) with 1.0% solution, 30-50mg, 300mg as the limit; Pubic nerve with 0.5%-1.0% solution, 100mg on the left and right sides.

(6) Sympathetic ganglion block: cervical stellate nerve with 1.0% solution, 50mg; Waist anesthesia with 1.0% solution, 50-100mg.

(7) One time limit, 200mg (4mg/kg) without adrenal glands, 300-350mg (6mg/kg) with epinephrine; Intravenous area blockade, maximum amount 4mg/kg; Intravenous injection for treatment, the first initial dose of 1-2mg/kg, the maximum amount of 4mg/kg, adult intravenous drip is limited to 1mg per minute; Repeated multiple administrations with an interval of not less than 45-60 minutes.

2. Commonly used amount for children

Depending on the individual, the total amount of one administration should not exceed 4.0-4.5mg/kg, 0.25%-0.5% solution is commonly used, and 1.0% solution is used in special circumstances.

Antiarrhythmic

1. Commonly used amount

(1) Intravenous injection: 1-1.5mg/kg body weight (generally 50-100mg) for the first load intravenous injection for 2-3 minutes, if necessary, repeat intravenous injection 1-2 times after every 5 minutes, but the total amount within 1 hour shall not exceed 300mg.

(2) Intravenous drip: generally 5% glucose injection is prepared into 1~4mg/mL drug infusion or administered with an infusion pump, and after the load, it can continue to be maintained intravenously at a rate of 1~4mg per minute, or intravenous drip at a rate of 0.015~0.03mg/kg body weight per minute. The elderly, heart failure, cardiogenic shock, decreased liver blood flow, liver or kidney dysfunction should reduce the dosage, to 0.5~1mg per minute intravenous drip. It can be intravenously instilled with 0.1% solution of the product, not exceeding 100mg per hour.

2. Extreme quantity

The maximum load within 1 hour of intravenous administration is 4.5 mg/kg body weight (or 300 mg). The maximum maintenance amount is 4 mg per minute.