From the Guidelines
Ingesting lidocaine can be life-threatening, and immediate medical attention is crucial if this occurs. Lidocaine is designed for topical or injectable use, not for oral consumption. When swallowed, lidocaine can cause serious systemic effects, including:
- Cardiovascular problems, such as irregular heartbeat and low blood pressure
- Central nervous system issues, like seizures, confusion, and dizziness
- Respiratory depression The severity of these effects depends on the amount ingested, with higher doses causing more serious complications, as noted in the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1. Initial symptoms might include numbness of the mouth and throat, which can progress to difficulty swallowing or breathing. Lidocaine toxicity occurs because when ingested, the drug enters the bloodstream directly rather than being metabolized first by the liver, leading to higher blood concentrations. If you suspect lidocaine ingestion, do not induce vomiting unless directed by healthcare professionals. Instead, call poison control or go to the emergency room immediately. Treatment typically involves supportive care, monitoring vital signs, and possibly medications to control seizures or cardiac symptoms, such as those caused by lidocaine toxicity, which includes myocardial and circulatory depression, drowsiness, disorientation, muscle twitching, and seizures, especially in patients with poor cardiac output and hepatic or renal failure 1.
From the FDA Drug Label
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 or rapid absorption, or may result from a hypersensitivity, idiosyncrasy, or diminished tolerance on the part of the patient 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.
If you ingest lidocaine, it can cause systemic toxicity due to high plasma levels. The effects on the Central Nervous System (CNS) can be either excitatory or depressant, and may include symptoms such as:
- 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 2 Cardiovascular effects can also occur, including bradycardia, hypotension, and cardiovascular collapse, which may lead to cardiac arrest. 2
From the Research
Ingestion of Lidocaine
If you ingest lidocaine, a local anesthetic, several adverse effects can occur. The severity of these effects depends on the concentration and amount of lidocaine ingested.
- Neurotoxic manifestations: These can appear at lower concentrations than cardiotoxic symptoms and are correlated with plasma levels of lidocaine 3. Symptoms include headache, hallucinations, seizures, coma, respiratory arrest, and circulatory collapse.
- Cardiotoxic symptoms: These are also correlated with plasma levels of lidocaine and can include cardiorespiratory arrest 3.
- Nausea and vomiting: Swallowing topically administered 4% lidocaine can result in a significant increase in the incidence of nausea and vomiting 4.
- Seizures: Lidocaine has a concentration-dependent effect on seizures. At lower concentrations, it has anticonvulsant properties, whereas concentrations above 15 microg/mL frequently result in seizures in laboratory animals and humans 5.
- Fatal intoxication: Accidental ingestion of viscous 2% lidocaine can be fatal, especially in young children 3.
Management of Lidocaine Ingestion
There is no antidote for acute lidocaine toxicity, and management is primarily supportive therapy, including: