Mechanism of Action
Clinical Pharmacology Mechanism of Action and Electrophysiology: Studies of the effects of therapeutic concentrations of lidocaine on the electrophysiological properties of mammalian Purkinje fibers have shown that lidocaine attenuates phase 4 diastolic depolarization, decreases automaticity and causes a decrease or no change in excitability and membrane responsiveness. Action potential duration and effective refractory period of Purkinje fibers are decreased while the ratio of effective refractory period to action potential duration is increased. Action potential duration and effective refractory period of ventricular muscle are also decreased. Effective refractory period of the AV node may increase, decrease or remain unchanged and atrial effective refractory period is unchanged.
Indications
- 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.
Common Doses
- 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.
Contraindications
- 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.
Side Effects
- 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.