Lidocaine Hydrochloride

INDICATIONS AND USAGE Lidocaine hydrochloride injection administered intravenously or intramuscularly, is specifically indicated in the acute management of ventricular arrhythmias such as those occurring in relation to acute myocardial infarction, or during cardiac manipulation, such as cardiac surgery.

DOSAGE AND ADMINISTRATION Adults: Single Direct Intravenous Injection (bolus): ONLY THE 5 mL, 50 MG or 100 MG DOSAGE SIZES should be used for direct intravenous injection. The usual dose is 50 to 100 mg of lidocaine hydrochloride (0.70 to 1.4 mg/kg; 0.32 to 0.63 mg/lb) administered intravenously under ECG monitoring. This dose may be administered at the rate of approximately 25 to 50 mg/min (0.35 to 0.70 mg/kg/min; 0.16 to 0.32 mg/lb/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 injected after five minutes. NO MORE THAN 200 TO 300 MG OF LIDOCAINE HYDROCHLORIDE SHOULD BE ADMINISTERED DURING A ONE HOUR PERIOD. Continuous Intravenous Infusion: Following bolus administration, intravenous infusions of lidocaine hydrochloride may be initiated at the rate of 1 to 4 mg/min of lidocaine hydrochloride (0.014 to 0.057 mg/kg/min; 0.006 to 0.026 mg/lb/min). The rate of intravenous infusions should be reassessed 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 of lidocaine for prolonged periods. When administering lidocaine hydrochloride (or any potent medication) by continuous intravenous infusion, it is advisable to use a precision volume control I.V. set. Pediatric: Controlled clinical studies in the pediatric population to establish dosing schedules have not been conducted. The American Heart Association's Standards and Guidelines recommends a bolus dose of 1 mg/kg, and an infusion rate of between 20-50 mcg/kg/min for prolonged therapy. When drug clearance is reduced, as in patients with shock, congestive heart failure or cardiac arrest, the infusion rate should not exceed 20 mcg/kg/min. NOTE: Regarding Prolonged Infusions: There are data that indicate the half-life may be 3 hours or longer following infusions of greater than 24 hours in duration. Do not use if solution is discolored or cloudy. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit. To prevent needle-stick injuries, needles should not be recapped, purposely bent or broken by hand.

WARNINGS IN ORDER TO MANAGE POSSIBLE ADVERSE REACTIONS, RESUSCITATIVE EQUIPMENT, OXYGEN AND OTHER RESUSCITATIVE DRUGS SHOULD BE IMMEDIATELY AVAILABLE WHEN LIDOCAINE HYDROCHLORIDE INJECTION IS USED. Systemic toxicity may result in manifestations of central nervous system depression (sedation) or irritability (twitching), which may progress to frank convulsions accompanied by respiratory depression and/or arrest. Early recognition of premonitory signs, assurance of adequate oxygenation and, where necessary, establishment of artificial airway with ventilatory support are essential to management of this problem. Should convulsions persist despite ventilatory therapy with oxygen, small increments of anticonvulsant drugs may be used intravenously. Examples of such agents include benzodiazepines (e.g., diazepam), ultrashort-acting barbiturates (e.g., thiopental or thiamylal) or a short-acting barbiturate (e.g., pentobarbital or secobarbital). If the patient is under anesthesia, a short-acting muscle relaxant (e.g., succinylcholine) may be used. Longer acting drugs should be used only when recurrent convulsions are evidenced. Should circulatory depression occur, vasopressors may be used. Constant electrocardiographic monitoring is essential to the proper administration of lidocaine hydrochloride. Signs of excessive depression of cardiac electrical activity such as sinus node dysfunction, prolongation of the P-R interval and QRS complex or the appearance or aggravation of arrhythmias, should be followed by flow adjustment and, if necessary, prompt cessation of the intravenous infusion of this agent. Occasionally, acceleration of ventricular rate may occur when lidocaine hydrochloride is administered to patients with atrial flutter or fibrillation.

CONTRAINDICATIONS Lidocaine hydrochloride is contraindicated in patients with a known history of hypersensitivity to local anesthetics of the amide type. Lidocaine hydrochloride should not be used in patients with Stokes-Adams syndrome, Wolff-Parkinson-White syndrome or with severe degrees of sinoatrial, atrioventricular or intraventricular block in the absence of an artificial pacemaker.

4. Drug Interactions: Lidocaine Hydrochloride Injection, USP should be used with caution in patients with digitalis toxicity accompanied by atrioventricular block. Concomitant use of beta-blocking agents or cimetidine may reduce hepatic blood flow and thereby reduce lidocaine clearance. The concomitant use of these two agents may cause an increased incidence of adverse reactions, including central nervous system adverse reactions such as seizure. Lidocaine and tocainide are pharmacodynamically similar.

6. Pregnancy: Teratogenic Effects: Reproduction studies have been performed in rats at doses up to 6.6 times the maximum human doses and have revealed no significant findings. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

8. Nursing Mothers: It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when lidocaine is administered to a nursing woman.

ADVERSE REACTIONS Adverse experiences following the administration of lidocaine are similar in nature to those observed with other amide local anesthetic agents. Adverse experiences may result from high plasma levels caused by excessive dosage or may result from a hypersensitivity, idiosyncrasy or diminished tolerance on the part of the patient. Serious adverse experiences are generally systemic in nature. The following types are those most commonly reported. The adverse experiences under Central Nervous System and Cardiovascular System are listed, in general, in a progression from mild to severe. Central Nervous System: CNS reactions are excitatory and/or depressant and may be characterized by light-headedness, nervousness, apprehension, euphoria, confusion, dizziness, drowsiness, tinnitus, blurred or double vision, vomiting, sensations of heat, cold or numbness, twitching, tremors, convulsions, unconsciousness, respiratory depression and arrest. The excitatory reactions may be very brief or may not occur at all, in which case, the first manifestation of toxicity may be drowsiness, merging into unconsciousness and respiratory arrest. Cardiovascular System: Cardiovascular reactions are usually depressant in nature and are characterized by bradycardia, hypotension and cardiovascular collapse, which may lead to cardiac arrest. Allergic reactions as a result of sensitivity to lidocaine are extremely rare and, if they occur, should be managed by conventional means. Neurologic: There have been reported cases of permanent injury to extraocular muscles requiring surgical repair following retrobulbar administration.