ve been reported in rare instances when
caudal or lumbar epidural block has been attempted. Backache and headache have also been noted following use of these anesthetic
procedures.
There have been reported cases of permanent injury to extraocular muscles requiring surgical repair following retrobulbar
administration.
OVERDOSAGE
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).
Management of Local Anesthetic Emergencies
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 unintended subarachnoid injection
of drug solution, 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 eva luated, 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 the 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 (eg, 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 unintentional subarachnoid injection of local anesthetic solution 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 HCl.
The oral LD50 of lidocaine HCl in non-fasted female rats is 459 (346 to 773) mg/kg (as the salt) and 214 (159 to 324) mg/kg (as the
salt) in fasted female rats.
DOSAGE & ADMINISTRATION
Table 1 (Recommended Dosages) summarizes the recommended volumes and concentrations of Xylocaine Injection for various
types of anesthetic procedures. The dosages suggested in this table are for normal healthy adults and refer to the use of epinephrinefree
solut
