By Katherine Kozlowski, Medical Author and Associate Editor at Vein News, VeinsVeinsVeins.com
The anesthetic lidocaine is a cream or injection that is commonly used for surgical and non-invasive procedures.
REACTIONS
The most common mild reactions to lidocaine are local skin reactions on the area it was applied. There are more severe risks including methemoglobinemia (red blood cells have less affinity for oxygen making it difficult to breathe), central nervous system toxicity, and cardiotoxicity.
The first, most common signs of toxicity are numbness around the mouth, tongue paresthesia, and dizziness, tinnitus, or blurred vision.
Other signs of toxicity include restlessness, agitation, nervousness, paranoia, twitches, and seizures. If there is a large overdose of lidocaine, unconsciousness and coma are the most severe reactions.
If lidocaine is unintentionally injected intravascularly, hypotension, atrioventricular heart block (slowing of the electrical impulses in the heart which can cause irregularities in heart contractions), idioventricular rhythms (irregular heartbeat from the ventricles), ventricular tachycardia (increased heart rate in the ventricles), ventricular fibrillation (ventricles beat faster and out of rhythm) are the usual presenting signs of cardiotoxicity.
TREATMENT
Lidocaine is lipid-soluble, meaning it can bind to fats. If a person is subject to lidocaine toxicity, lipid infusions into the plasma can bind free anesthetic in the blood and thus lower the blood levels of lidocaine.
Other treatments include the management of associated symptoms including seizure suppression with medications, airway ventilation, or cardiovascular resuscitation.
References:
Torp K, Metheny E, Simon L. Lidocaine Toxicity. StatPearls 2020.
Tran A and Koo J. Risk of systemic toxicity with topical lidocaine/prilocaine: a review. J Drugs Dermatol 2014; 13 (9): 1118-1122.