Lidocaine Hydrochloride Anhydrous and Dextrose Monohydrate

INDICATIONS AND USAGE Lidocaine hydrochloride administered intravenously is specifically indicated in the acute management of (1) ventricular arrhythmias occurring during cardiac manipulations, such as cardiac surgery and (2) life-threatening arrhythmias which are ventricular in origin, such as occur during acute myocardial infarction.

DOSAGE AND ADMINISTRATION Therapy of ventricular arrhythmias is often initiated with a single IV bolus of 1 mg/kg of Lidocaine Hydrochloride Injection USP. Following acute treatment by bolus in patients in whom arrhythmias tend to recur and who are incapable of receiving oral antiarrhythmic agents, intravenous infusion of Lidocaine Hydrochloride and 5% Dextrose Injection USP is administered continuously. Rate of Administration Adults (20 to 50 mcg/kg/min): Average 70 kg adult mg/min mL/hr mL/min 0.4% Lidocaine Hydrochloride and 5% Dextrose Injection USP (4 mg lidocaine hydrochloride/mL) 1–4 15–60 0.25–1.0 0.8% Lidocaine Hydrochloride and 5% Dextrose Injection USP (8 mg lidocaine hydrochloride/mL) 1–4 7.5–30 0.12–0.5 Pediatric Patients (30 mcg/kg/min). Standards and Guidelines for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiac Care (ECC). American Heart Association, JAMA 244 (5):453–509, 1980. Pharmacokinetic data indicate reduced elimination of lidocaine after prolonged infusion (24 hours) with resultant prolongation of the half-life to approximately three times that seen following a single administration. Failure to adjust the rate of infusion in keeping with this altered ability to eliminate lidocaine may result in toxic accumulation of the drug in the patient's serum. LeLorier J, Grenon D, Latour Y, et al.: Pharmacokinetics of lidocaine after prolonged intravenous infusions in uncomplicated myocardial infarction. Ann Int Med 87:700–702, 1977. Intravenous infusions of lidocaine hydrochloride must be administered under constant ECG monitoring to avoid potential overdosage and toxicity. Intravenous 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 intravenous infusions beyond 24 hours. As soon as possible and when indicated, patients should be changed to an oral antiarrhythmic agent for maintenance therapy. Caution: Concentrated solutions of lidocaine hydrochloride (greater than 0.2%) should be administered by carefully calibrated infusion devices. Pediatric Use Therapy should be initiated with a single IV bolus of 1 mg/kg of Lidocaine Hydrochloride Injection USP. A maintenance intravenous infusion of Lidocaine Hydrochloride and 5% Dextrose Injection USP administered at a recommended infusion rate of 30 mcg/kg/min may be given. Geriatric Use Patients with reduced hepatic function or diminished hepatic blood flow (as in heart failure and after cardiac surgery), or those over 70 years of age should receive half the usual loading dose and also should be given lower maintenance levels of intravenous lidocaine. Patients over 65 years may benefit from dosing based upon body weight (see CLINICAL PHARMACOLOGY and PRECAUTIONS, Geriatric Use ). Lidocaine hydrochloride should not be added to blood transfusion assemblies. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

WARNINGS Constant monitoring with an electrocardiograph is essential to the proper administration of lidocaine hydrochloride intravenously. Signs of excessive depression of cardiac conductivity, such as prolongation of the PR interval, widening of the QRS interval or the appearance or aggravation of arrhythmias, should be followed by prompt cessation of the intravenous infusion of this agent. It is mandatory to have emergency resuscitative equipment and drugs immediately available to manage adverse reactions involving cardiovascular, respiratory, or central nervous systems. Occasional acceleration of ventricular rate may occur when lidocaine hydrochloride is administered to patients with atrial fibrillation. Evidence for proper usage in pediatric patients is limited. Anaphylactic reactions may occur following administration of lidocaine hydrochloride. In the case of severe reaction, discontinue the use of the drug. Because dosages of this drug are titrated to response (see DOSAGE AND ADMINISTRATION ), no additives should be made to Lidocaine Hydrochloride and 5% Dextrose Injection USP .

CONTRAINDICATIONS Lidocaine hydrochloride is contraindicated in patients with a known history of hypersensitivity to local anesthetics of the amide type. Lidocaine should not be used in patients with Stokes-Adams syndrome, Wolff-Parkinson-White syndrome, or with severe degrees of sinoatrial, atrioventricular, or intraventricular block. Solutions containing dextrose may be contraindicated in patients with known allergy to corn or corn products.

Drug Interactions Lidocaine should be used with caution in patients with digitalis toxicity accompanied by atrioventricular block (see CONTRAINDICATIONS ). Coadministration of propranolol or cimetidine with lidocaine has been reported to reduce clearance from the plasma and may result in toxic accumulation of the drug (see CLINICAL PHARMACOLOGY ). When lidocaine is administered with other antiarrhythmic drugs such as phenytoin, procainamide, propranolol, amiodarone, or quinidine, the cardiac effects may be additive or antagonistic and toxic effects may be additive. Phenytoin may stimulate the hepatic metabolism of lidocaine, but the clinical significance of this effect is not known.

ADVERSE REACTIONS Systemic reactions of the following types have been reported: Central Nervous System: Light-headedness; drowsiness; dizziness; apprehension; euphoria; tinnitus; blurred or double vision; nausea and vomiting; sensation of heat, cold or numbness; twitching; tremors; convulsions; unconsciousness; respiratory depression and arrest. Cardiovascular System: Hypotension; cardiovascular arrest; and bradycardia which may lead to cardiac arrest. Hematologic Effects: methemoglobinemia Allergic reactions, including anaphylactic reactions, may occur but are infrequent. There have been no reports of cross-sensitivity between lidocaine hydrochloride and procainamide or between lidocaine hydrochloride and quinidine.

CLINICAL PHARMACOLOGY Lidocaine hydrochloride exerts an antiarrhythmic effect by increasing the electric stimulation threshold of the ventricle during diastole. In usual therapeutic doses, lidocaine hydrochloride produces no change in myocardial contractility, in systemic arterial pressure, or in absolute refractory period. About 90% of an administered dose of the drug is metabolized in the liver. The remaining 10% is excreted unchanged via the kidneys. Lidocaine toxicity is related to systemic blood levels. The decreased clearance and longer half-life of lidocaine should be taken into consideration with prolonged (24 hour) infusions. Constant rate of infusion may result in toxic accumulation of lidocaine. Infusion should be reduced to approximately one-half to compensate for decreased rate of clearance and concomitant or prior administration of propranolol may further increase blood concentrations by as much as 30% in patients without cardiac or hepatic failure. In clinical studies, patients over 65 years showed decreased lidocaine clearance. This was partly due to the tendency of elderly patients to have lower body weight and the increased risk of cardiac failure in these patients. This solution provides approximately 170 calories per liter.