From the Guidelines
Lidocaine toxicity presents with symptoms that progress in severity as blood levels increase, including early signs such as lightheadedness, dizziness, perioral numbness, tinnitus, metallic taste, and visual disturbances, as well as more severe symptoms like confusion, slurred speech, muscle twitching, tremors, and seizures, with cardiovascular symptoms including hypotension, bradycardia, arrhythmias, and in severe cases, cardiovascular collapse 1.
Symptoms of Lidocaine Toxicity
The symptoms of lidocaine toxicity can be categorized into central nervous system (CNS) and cardiovascular symptoms. CNS symptoms include:
- Lightheadedness
- Dizziness
- Perioral numbness
- Tinnitus
- Metallic taste
- Visual disturbances
- Confusion
- Slurred speech
- Muscle twitching
- Tremors
- Seizures Cardiovascular symptoms include:
- Hypotension
- Bradycardia
- Arrhythmias
- Cardiovascular collapse
Risk Factors and Treatment
Risk factors for lidocaine toxicity include liver disease, heart failure, renal impairment, and drug interactions that affect lidocaine metabolism 1. Treatment involves stopping lidocaine administration, providing supportive care, managing seizures with benzodiazepines, and in severe cases, advanced cardiac life support measures, with the administration of intravenous lipid emulsion recommended for local anesthetic poisoning 1.
Management of Local Anesthetic Poisoning
The management of local anesthetic poisoning, including lidocaine toxicity, involves the use of benzodiazepines to treat seizures, and the administration of sodium bicarbonate for life-threatening wide-complex tachycardia, as well as the consideration of atropine for life-threatening bradycardia and extracorporeal life support techniques for refractory cardiogenic shock 1.
From the FDA Drug Label
ADVERSE REACTIONS 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: Central nervous system manifestations are excitatory and/or depressant and may be characterized by light-headedness, 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. Cardiovascular system: Cardiovascular manifestations are usually depressant and are characterized by bradycardia, hypotension, and cardiovascular collapse, which may lead to cardiac arrest.
The symptoms of lidocaine toxicity may include:
- Central nervous system manifestations:
- Excitatory: light-headedness, nervousness, apprehension, euphoria, confusion, dizziness, tinnitus, blurred or double vision, vomiting, sensations of heat, cold or numbness, twitching, tremors, convulsions
- Depressant: drowsiness, unconsciousness, respiratory depression and arrest
- Cardiovascular system manifestations: bradycardia, hypotension, and cardiovascular collapse, which may lead to cardiac arrest 2
From the Research
Symptoms of Lidocaine Toxicity
The symptoms of lidocaine toxicity can be severe and life-threatening, affecting the central nervous system (CNS) and cardiovascular system. Some of the symptoms include:
- Perioral numbness 3
- Seizure-like activity 3, 4
- Confusion 3
- Diffuse tremors 4
- Paresthesias of the mouth and face 4
- Spasticity 4
- Irritability 4
- Generalized tonic-clonic seizure 4
- Cardiac arrest 5, 6, 7
Treatment of Lidocaine Toxicity
Treatment of lidocaine toxicity often involves the use of intravenous lipid emulsion (ILE) as an antidote 5, 3, 7. ILE has been shown to be effective in treating the cardiotoxic effects of lidocaine and other local anesthetics. In some cases, other medications such as Ativan may also be used in conjunction with ILE to treat symptoms such as seizures 4.
Importance of Early Recognition and Treatment
Early recognition and treatment of lidocaine toxicity are crucial to prevent serious complications and improve patient outcomes. Healthcare providers should be trained in the treatment and prevention of local anesthetic systemic toxicity (LAST) and should have a low threshold of suspicion for lidocaine toxicity when patients present with neurologic or cardiovascular symptoms following exposure to the drug 3, 4.