Lidocaine Injection is Helpful in Anesthesia and Arrhythmia
Lidocaine injection is a common local anesthetic and antiarrhythmic drug. Arrhythmia is a condition where the patient experience irregular heartbeats. Lidocaine is injected as a dental anesthetic, and in minor surgery. This drug may also be used for resistant seizure treatment.
Lidocaine injection is commonly given by vein (IV). It may also be given in a large muscle (IM - in the shoulder) for one or two doses if required. By and large 50-100mg is given first IV, and then repeated if necessary. This dosing is accompanied by continuous IV therapy (1-4 mg per minute typically). In people having heart failure or liver problems, the doses may need to be reduced.
Dosage
The dose of lidocaine injection needed for anesthesia may vary according the type of procedure, degree of anesthesia required, and the patient’s response. For use in children, elderly, or debilitated patients, the dose should usually be reduced. In average healthy adults, the maximum recommended dose of lidocaine injection with epinephrine for local anesthesia except spinal should not go beyond 7 mg/Kg, and the maximum total dose should not exceed 500 mg. Lidocaine injection with epinephrine are not supposed to be used on fingers and toes. In case of lidocaine injection without epinephrine, the maximum recommended dose should not be more than 4.5 mg/Kg, and the maximum total dose should not exceed 300 mg. Once given the maximum dose of lidocaine, do not repeat for 2 hours.
Adverse Drug Reactions
Lidocaine injection causes very rare adverse drug reactions if it is used as a local anesthetic and is administered correctly. Most drug reaction caused by this medication for anesthesia concern administration technique (resulting in systemic exposure) or pharmacological effects of anesthesia, but allergic reactions can rarely occur.
Systemic exposure to excessive quantities of lidocaine mainly causes central nervous system (CNS) and cardiovascular effects. CNS effects typically arise at lower blood plasma concentrations and additional cardiovascular effects present at higher concentrations, though cardiovascular collapse may also occur with low concentrations. Among the CNS effects, it covers tinnitus, CNS excitation (nervousness, tingling around the mouth (also known as circumoral paraesthesia), tremor, dizziness, blurred vision, seizures) followed by depression, and with increasingly heavier exposure: drowsiness, loss of consciousness, respiratory depression and apnoea). Cardiovascular effects incorporate arrhythmias, hypotension, bradycardia, and/or cardiac arrest – some of which may be caused by hypoxemia secondary to respiratory depression.
ADRs related to the use of intravenous lidocaine are same to toxic effects from systemic exposure above. These are dose-related and more frequent at high infusion rates (≥3 mg/minute). Common ADRs include: headache, dizziness, drowsiness, confusion, visual disturbances, tinnitus, tremor, and/or paraesthesia. Infrequent ADRs associated with the use of lidocaine include: hypotension, bradycardia, arrhythmias, cardiac arrest, muscle twitching, seizures, coma, and/or respiratory depression.
Warnings
Lidocaine hydrochloride injection, for infiltration and nerve block, should be in use only by clinical persons who have knowledge in diagnosis and management of dose-related risk and other acute emergencies that might be caused by the block to be in use and then only after ensuring the immediate availability of oxygen, other resuscitative drugs, cardiopulmonary equipment and the personnel needed for proper management of toxic reactions and related emergencies. If proper management of dose-related toxicity is deferred under ventilation from any cause and/or altered sensitivity, it may result in acidosis, cardiac arrest and, probably, death.
To stay away from intravascular injection, aspiration should be made before the local anesthetic solution is injected. The needle should be repositioned until no return of blood can be obtained by aspiration. Note, that the absence of blood in the syringe gives no guarantee that intravascular injection has been avoided.