Lidocaine Side Effects

Some side effects of lidocaine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to lidocaine: injectable solution

Get emergency medical help if you have any of these signs of an allergic reaction while taking lidocaine: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Tell your caregivers at once if you have any of these serious side effects:

• feeling anxious, shaky, dizzy, restless, or depressed;

• drowsiness, vomiting, ringing in your ears, blurred vision;

• confusion, twitching, seizure (convulsions);

• fast heart rate, rapid breathing, feeling hot or cold;

• weak or shallow breathing, slow heart rate, weak pulse; or

• feeling like you might pass out.

Less serious side effects include:

• mild bruising, redness, itching, or swelling where the medication was injected;

• mild dizziness;

• nausea;

• numbness in places where the medicine is accidentally applied.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to lidocaine: compounding powder, injectable solution

General

Adverse side effects of lidocaine may be more likely and more severe in patients with liver disease.

The overall incidence of adverse side effects of lidocaine in a study of 750 patients was 6.3%. Adverse drug reactions were more common in patients with acute myocardial infarction, congestive heart failure, and liver disease. In another large study of 285 patients with suspected or documented acute myocardial infarction who received prophylactic intravenous lidocaine, more adverse events occurred in patients who received drug versus patients who received placebo. The most adverse events were recorded within the first hour of therapy in patients who eventually proved not to have myocardial infarction. Adverse events were not necessarily correlated with high lidocaine levels.

Cardiovascular

Cardiovascular side effects occur in 2% of patients. Serious cardiovascular problems include hypotension and cardiopulmonary arrest. Rare cases of asystole have been reported after lidocaine administration with and without other antiarrhythmic agents. Less commonly, negative inotropic activity, sinus node depression, torsades de pointes, and AV or His-Purkinje block have been reported.

An 84-year-old man with ischemic congestive heart failure, nonsustained ventricular tachycardia, and incomplete left bundle branch block developed sinus bradycardia, then asystole within five minutes after beginning a lidocaine 100 mg bolus and 2 mg per min infusion. Atropine was initially unsuccessful, but normal sinus rhythm resumed after approximately 20 seconds. Serum electrolytes were within normal limits at the time; arterial pO2 was not reported. A follow-up 24-hour ambulatory ECG failed to demonstrate evidence of AV heart block or bradyarrhythmias.

Nervous system

Toxicity is usually associated with serum lidocaine concentrations of 9 to 10 mcg per mL, but may occur with concentrations as low as 5 mcg/mL. Central nervous system toxicity has been observed in patients with hepatic cirrhosis who were receiving lidocaine at infusion rates as low as 2.2 to 2.5 mg per min.

Transient neurologic symptoms (TNS), characterized as a symptom complex of acute onset low back pain with transient radiating pain into the buttocks and lower extremities, have been associated with the use of intrathecal hyperbaric lidocaine. TNS typically occurs within 24 hours after spinal anesthesia and resolves within 1 week without lasting sequelae. TNS has been reported in up to 40% of patients receiving intrathecal lidocaine; however, in at least two studies involving obstetric patients undergoing cesarean section or postpartum tubal ligation, the incidence of TNS did not exceed 3% following use of hyperbaric lidocaine 5%. Some practitioners consider TNS a minor manifestation of the cauda equine syndrome. It is thought that patient position may be a contributing factor to the development of TNS.

Lidocaine toxicity often presents as nervous system side effects. Yawning, restlessness, excitement, agitation, dizziness, blurred vision, muscle twitching, confusion, tinnitus, drowsiness, vertigo, paresthesias, and even seizures and respiratory arrest have been reported. Rare cases of seizures following topical or subcutaneous administration of lidocaine have been reported. Transient neurologic symptoms have been reported following intrathecal lidocaine.

Gastrointestinal

Nausea and vomiting are common gastrointestinal symptoms of lidocaine toxicity.

Hypersensitivity

A previously healthy 27-year-old woman, pre-Cesarean section, with a history of possible hypersensitivity to bupivacaine developed tongue tingling, faintness, and nausea associated with hypotension 25 minutes after receiving bupivacaine as local anesthesia for an epidural catheter. She became progressively erythematous, pruritic, and edematous. The patient responded well to fluids, oxygen, a sympathomimetic, antihistamines, and corticosteroids. The neonate, born after emergency Cesarean section, was limp, cyanotic, edematous, and required mechanical ventilation secondary to pulmonary edema. Follow-up investigations in the mother revealed moderately raised total plasma IgE levels and positive intradermal wheal formation to 2% lidocaine.

Hypersensitivity reactions are rare. Anaphylaxis, adult respiratory distress syndrome (ARDS), and cardiovascular collapse have been associated with the use of lidocaine, and have occasionally resulted in death. Cases of angioneurotic edema, anaphylaxis, bronchospasm, and urticaria following local anesthesia with lidocaine have been reported. Contact dermatitis associated with lidocaine has been described in chemical and health care workers. Patients with a history of an allergic reaction to local amide-type anesthetics may react to lidocaine. Delayed-type hypersensitivity reactions to lidocaine have also been reported.

Psychiatric

Psychiatric reactions have been associated with lidocaine toxicity. Several case reports of acute psychosis associated with lidocaine infusions have been reported. It is not clear from the case reports whether these reactions were associated with therapeutic or toxic serum levels of lidocaine.

Several cases of acute and reversible psychoses have been reported in several patients, most of whom were in their sixth decade of life or older and who were receiving intravenous lidocaine.

Hematologic

Hematologic abnormalities associated with lidocaine have been limited to rare reports of significant increases in methemoglobin levels during lidocaine infusions. These increases are usually not clinically significant, however, at least one case of acute topical benzocaine-induced methemoglobinemia of 29% has been reported.

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