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, 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 HCl is usually an early sign of a high blood level of the drug and may occur as a
consequence of rapid absorption.
Cardiovascular System
Cardiovascular manifestations are usually depressant and are characterized by bradycardia, hypotension, and cardiovascular collapse,
which may lead to cardiac arrest.
Allergic
Allergic reactions are characterized by cutaneous lesions, urticaria, edema or anaphylactoid reactions. Allergic reactions may occur
as a result of sensitivity either to local anesthetic agents or to the methylparaben used as a preservative in the multiple dose vials.
Allergic reactions as result of sensitivity to lidocaine HCl are extremely rare and, if they occur, should be managed by conventional
means. The detection of sensitivity by skin testing is of doubtful value.
Neurologic
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 HCl 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.
In the practice of caudal or lumbar epidural block, occasional unintentional penetration of the subarachnoid space by the catheter
may occur. Subsequent adverse effects may depend partially on the amount of drug administered subdurally. These may include
spinal block of varying magnitude (including total spinal block), hypotension secondary to spinal block, loss of bladder and bowel
control, and loss of perineal sensation and sexual function. Persistent motor, sensory and/or autonomic (sphincter control) deficit of
some lower spinal segments with slow recovery (several months) or incomplete recovery have 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 subarac |
