Safety and effectiveness in pediatric patients below the age of 16 years have not been established.
Adverse experiences following the administration of lidocaine are similar in nature to those observed with other amide local anesthetic agents. These adverse experiences are, in general, dose-related and may result from high plasma levels caused by excessive dosage, rapid absorption or inadvertent intravascular injection, 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:
Central nervous system
CNS manifestations are excitatory and/or depressant and may be characterized by lightheadedness, nervousness, apprehension, euphoria, confusion, dizziness, lethargy, slurred speech, drowsiness, tinnitus, blurred or double vision, vomiting, sensations of heat, cold or numbness, twitching, tremors, convulsions, unconsciousness, respiratory depression and arrest. The excitatory manifestations 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.
Drowsiness following the administration of lidocaine is usually an early sign of a high blood level of the drug and may occur as a consequence of rapid absorption.
Cardiovascular manifestations are usually depressant and are characterized by bradycardia, hypotension, and cardiovascular collapse, which may lead to cardiac arrest.
Allergic reactions are characterized by cutaneous lesions, urticaria, edema or anaphylactoid reactions. Allergic reactions as a result of sensitivity to lidocaine are extremely rare and, if they occur, should be managed by conventional means. The detection of sensitivity by skin testing is of doubtful value.
The incidences of adverse reactions associated with the use of local anesthetics may be related to the total dose of local anesthetic administered and are also dependent upon the particular drug used, the route of administration and the physical status of the patient. In a prospective review of 10,440 patients who received lidocaine for spinal anesthesia, the incidences of adverse reactions were reported to be about 3 percent each for positional headaches, hypotension and backache; 2 percent for shivering; and less than 1 percent each for peripheral nerve symptoms, nausea, respiratory inadequacy and double vision. Many of these observations may be related to local anesthetic techniques, with or without a contribution from the local anesthetic.
Neurologic effects following spinal anesthesia may include loss of perineal sensation and sexual function; persistent anesthesia, paresthesia, weakness and paralysis of the lower extremities, and loss of sphincter control all of which may have slow, incomplete, or no recovery; hypotension; high or total spinal block; urinary retention; headache; backache; septic meningitis; meningismus, arachnoiditis; slowing of labor; increased incidence of forceps delivery; shivering; cranial nerve palsies due to traction on nerves from loss of cerebrospinal fluid; and fecal and urinary incontinence.
Acute emergencies from local anesthetics are generally related to high plasma levels encountered during therapeutic use of local anesthetics or to unintended subarachnoid injection of local anesthetic solution (see ADVERSE REACTIONS, WARNINGS, and PRECAUTIONS).
The first consideration is prevention, best accomplished by careful and constant monitoring of cardiovascular and respiratory vital signs and the patient’s state of consciousness after each local anesthetic injection. At the first sign of change, oxygen should be administered.
The first step in the management of convulsions, as well as underventilation or apnea due to excessive cephalad spread of the spinal block, consists of immediate attention to the maintenance of a patent airway and assisted or controlled ventilation with oxygen and a delivery system capable of permitting immediate positive airway pressure by mask. Immediately after the institution of these ventilatory measures, the adequacy of the circulation should be evaluated, keeping in mind that drugs used to treat convulsions sometimes depress the circulation when administered intravenously. Should convulsions persist despite adequate respiratory support, and if the status of the circulation permits, small increments of an ultra-short acting barbiturate (such as thiopental or thiamylal) or a benzodiazepine (such as diazepam) may be administered intravenously. The clinician should be familiar, prior to use of local anesthetics, with these anticonvulsant drugs. Supportive treatment of circulatory depression may require administration of intravenous fluids and, when appropriate, a vasopressor as directed by the clinical situation (e.g., ephedrine).
If not treated immediately, both convulsions and cardiovascular depression can result in hypoxia, acidosis, bradycardia, arrhythmias and cardiac arrest. Underventilation or apnea due to excessive cephalad spread of the spinal block may produce these same signs and also lead to cardiac arrest if ventilatory support is not instituted. If cardiac arrest should occur, standard cardiopulmonary resuscitative measures should be instituted.
Endotracheal intubation, employing drugs and techniques familiar to the clinician, may be indicated, after initial administration of oxygen by mask, if difficulty is encountered in the maintenance of a patent airway or if prolonged ventilatory support (assisted or controlled) is indicated.
Dialysis is of negligible value in the treatment of acute overdosage with lidocaine.
The intravenous LD50 of lidocaine HCl in female mice is 26 (21 to 31) mg/kg and subcutaneous LD50 is 264 (203 to 304) mg/kg.
Spinal anesthesia with 5% Lidocaine Hydrochloride and 7.5% Dextrose Injection, USP may be induced in the right or left lateral recumbent or the sitting position. Since this is a hyperbaric solution, the anesthetic will tend to move in the direction in which the table is tilted. After the desired level of anesthesia is obtained and the anesthetic has become fixed, usually in 5 to 10 minutes with lidocaine, the patient may be positioned according to the requirement of the surgeon or obstetrician.
In clinical trials, the safety of hyperbaric lidocaine for single injection spinal anesthesia was demonstrated using 22 or 25 gauge spinal needles. In these studies, free flow of CSF was visible before injection of lidocaine.
Neurologic deficits have been reported with the use of small bore needles and microcatheters for spinal anesthesia. It has been postulated, based on in vitro models, that these deficits were caused by pooling and non-uniform distribution of concentrated local anesthetic within the subarachnoid space.1 Animal studies suggest mixing of 5% lidocaine hydrochloride with an equal volume of CSF or preservative-free 0.9% saline solution may reduce the risk of nerve injury due to pooling of concentrated local anesthetic2 (see PRECAUTIONS).
Intrathecal distribution of anesthetic may be facilitated by using a spinal needle of sufficient gauge to insure adequate withdrawal of CSF through the needle prior to and after anesthetic administration. If the technique is properly placed in the subarachnoid space, a separate injection is seldom necessary.
An incomplete or patchy block not responsive to patient repositioning may indicate misplacement or inadequate distribution of drug. To avoid excessive drug pooling, additional doses of lidocaine should not be administered with the same needle placement.
INJECTIONS SHOULD BE MADE SLOWLY. Consult standard textbooks for specific techniques for spinal anesthetic procedures.
There have been adverse event reports of chondrolysis in patients receiving intra-articular infusions of local anesthetics following arthroscopic and other surgical procedures. 5% Lidocaine Hydrochloride and 7.5% Dextrose Injection, USP is not approved for this use (see WARNINGS and DOSAGE AND ADMINISTRATION).
The following recommended dosages are for normal healthy adults and serve only as a guide to the amount of anesthetic required for most routine procedures. In all cases, the smallest dose that will produce the desired result should be given.
If the technique is properly performed, and the needle is properly placed in the subarachnoid space, it should not be necessary to administer more than one ampul (100 mg).
The dosage recommended for normal vaginal delivery is approximately 1 mL (50 mg). For Caesarean section and those deliveries requiring intrauterine manipulations, 1.5 mL (75 mg) is usually adequate.
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