LIDOCATON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LIDOCATON (LIDOCATON).
Lidocaine is a class IB antiarrhythmic agent that blocks voltage-gated sodium channels, inhibiting the inward sodium current, thereby stabilizing cardiac membranes, decreasing automaticity, and increasing the fibrillation threshold. It also acts as a local anesthetic by reversibly blocking nerve impulse propagation.
| Metabolism | Primarily hepatic via CYP1A2 and CYP3A4 to active metabolites (monoethylglycinexylidide and glycinexylidide). Less than 10% excreted unchanged in urine. |
| Excretion | Renal: ~90% as metabolites (major metabolite 4-hydroxyxylidine) and ~10% unchanged. Biliary/fecal: <5%. |
| Half-life | Terminal half-life 1.5–2 hours (adults); prolonged in heart failure (up to 4–6 hours) or hepatic impairment (up to 8 hours). |
| Protein binding | ~65–75% bound primarily to alpha-1-acid glycoprotein (AAG) and albumin. |
| Volume of Distribution | Vd 1.1–1.6 L/kg (increases in heart failure, liver disease). Large Vd indicates extensive tissue distribution. |
| Bioavailability | IM: ~100% (bioequivalent to IV). Oral: <35% due to extensive first-pass metabolism. Topical: variable, <10% systemically. |
| Onset of Action | IV: 45–90 seconds; IM: 5–15 minutes; Oral (not used systemically): N/A; Topical: 2–5 minutes. |
| Duration of Action | IV bolus: 10–20 minutes; IM: 60–90 minutes; Topical: 30–60 minutes. Duration shortened by rapid redistribution. |
| Molecular Weight | 234.34 |
Lidocaine: Initial IV bolus 1-1.5 mg/kg, then IV infusion 1-4 mg/min. Adjust for arrhythmia suppression.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment needed for GFR >30 mL/min. For GFR 10-30 mL/min, reduce maintenance infusion by 25%. For GFR <10 mL/min, reduce infusion by 50% and monitor. |
| Liver impairment | Child-Pugh Class A: no adjustment. Class B: reduce initial bolus by 25% and infusion by 50%. Class C: reduce bolus by 50% and infusion by 75%. |
| Pediatric use | Loading dose: 1 mg/kg IV, may repeat once. Maintenance infusion: 20-50 mcg/kg/min. Maximum 5 mg/kg total loading. |
| Geriatric use | Reduce initial bolus and maintenance infusion by 25-50% due to decreased clearance; monitor for CNS toxicity. |
| 1st trimester | Contraindicated: risk of fetal cardiac arrhythmias |
| 2nd trimester | Contraindicated: risk of fetal cardiac arrhythmias |
| 3rd trimester | Contraindicated: risk of fetal cardiac arrhythmias |
Clinical note
Comprehensive clinical and safety monograph for LIDOCATON (LIDOCATON).
| Placental transfer | Crosses placenta rapidly; fetal concentrations 50-70% of maternal |
| Breastfeeding | Excreted into breast milk; limited data suggest low risk at maternal doses, but monitor infant for bradycardia and apnea |
| Lactation Rating | L2 (Probably Compatible) |
■ FDA Black Box Warning
No FDA black box warning for lidocaine. However, use of lidocaine with epinephrine in digits or appendages may lead to ischemic necrosis.
| Serious Effects |
Hypersensitivity to lidocaine or amide anestheticsStokes-Adams syndromeWolff-Parkinson-White syndromeSevere sinoatrial block without pacemaker
| Precautions | Cardiotoxicity: bradycardia, hypotension, asystole, especially with high doses or rapid IV administration, Central nervous system toxicity: seizures, respiratory depression, confusion, Methemoglobinemia (rare, with high doses or in patients with G6PD deficiency), Use with caution in liver disease, heart failure, elderly, and patients with hypovolemia |
| Food/Dietary | No significant food interactions. Grapefruit juice does not affect lidocaine metabolism. Avoid excessive caffeine or stimulants during intravenous lidocaine use due to potential additive CNS effects. |
Loading safety data…
| Teratogenic Risk | Lidocaton is not a recognized drug. Assuming lidocaine: First trimester: No increased risk of major malformations based on large cohort studies. Second and third trimesters: No evidence of fetal toxicity at standard doses; high doses may cause fetal bradycardia or CNS depression. |
| Fetal Monitoring | Monitor maternal heart rate, blood pressure, and signs of local anesthetic systemic toxicity (LAST). Fetal heart rate monitoring during labor if using epidural or high-dose lidocaine. |
| Fertility Effects | No known adverse effects on fertility in animal studies. No human data suggesting impairment of fertility. |
| Clinical Pearls | Lidocaine is a class Ib antiarrhythmic and local anesthetic. For arrhythmias, use only for ventricular arrhythmias (especially post-MI) per ACLS guidelines; avoid in atrial fibrillation/flutter. Monitor for CNS toxicity (perioral numbness, metallic taste, seizures) with high doses. Hepatic impairment reduces clearance; adjust dose in heart failure or liver disease. The addition of epinephrine (1:100,000) prolongs local anesthetic effect and reduces systemic absorption for infiltration/nerve blocks. |
| Patient Advice | Inform your doctor if you have liver disease, heart problems, or a history of seizures. · For injections: temporary numbness or tingling is expected. Report persistent pain, swelling, or signs of infection at injection site. · For cardiac use: report any dizziness, confusion, ringing in ears, or unusual heartbeat changes immediately. · Do not drive or operate machinery immediately after receiving lidocaine injection until numbness resolves. · Avoid alcohol consumption while using lidocaine products, as it may increase side effects. |