LIDOCAINE HYDROCHLORIDE W/ EPINEPHRINE
Clinical safety rating: safe
Beta-blockers may increase the risk of lidocaine toxicity Can cause CNS toxicity (seizures) and cardiovascular collapse.
Lidocaine is a sodium channel blocker that inhibits voltage-gated sodium channels, preventing depolarization and conduction of nerve impulses. Epinephrine is an alpha- and beta-adrenergic agonist that causes vasoconstriction, reducing systemic absorption of lidocaine and prolonging local anesthetic effect.
| Metabolism | Lidocaine: primarily hepatic via CYP1A2 and CYP3A4; major metabolite monoethylglycinexylidide (MEGX) and glycinexylidide (GX). Epinephrine: metabolized by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO). |
| Excretion | Renal: unchanged drug <10%, major metabolites (MEGX and GX) ~70% renal; biliary: <10% fecal; total clearance ~10-20 mL/min/kg. Renal impairment prolongs elimination of metabolites. |
| Half-life | Terminal half-life 1.5-2 hours (single dose), prolonged to 2-3 hours with continuous infusion; in heart failure or hepatic cirrhosis, half-life may exceed 5 hours. |
| Protein binding | ~65-75% bound primarily to alpha-1-acid glycoprotein (AAG); binding is concentration-dependent and increases with AAG levels (e.g., inflammation, stress). |
| Volume of Distribution | Vd ~1.0-1.5 L/kg; decreased in heart failure (0.5-0.8 L/kg) and increased in hepatic disease (up to 2.0 L/kg). |
| Bioavailability | IM: 100% (intravascular absorption); oral: <15% due to extensive first-pass hepatic metabolism; epidural: ~100% (systemic absorption). |
| Onset of Action | IV: 45-90 seconds; IM: 10-15 minutes; epidural: 5-15 minutes; subcutaneous infiltration: immediate. |
| Duration of Action | IV: 10-20 minutes (single dose); IM: 60-90 minutes; epidural: 60-120 minutes; with epinephrine, duration extended by ~50% due to vasoconstriction. |
Local anesthesia: 1-5 mL of 1% or 2% solution with epinephrine 1:100,000 or 1:200,000; maximum dose 7 mg/kg lidocaine (500 mg without epinephrine, 7 mg/kg with epinephrine) per procedure. Intravenous: 1-1.5 mg/kg bolus for ventricular arrhythmias, followed by continuous infusion 1-4 mg/min.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for lidocaine; however, active metabolite MEGX may accumulate in severe renal impairment (GFR <15 mL/min), consider monitoring for toxicity. No specific GFR-based dose modifications. |
| Liver impairment | Child-Pugh Class A: No adjustment. Child-Pugh Class B: Reduce dose by 50% or prolong dosing interval. Child-Pugh Class C: Reduce dose by 50-75% or use alternative. Lidocaine clearance is significantly decreased in severe hepatic impairment. |
| Pediatric use | Local anesthesia: Max 4.5 mg/kg lidocaine with epinephrine (1:100,000), not to exceed single dose. Intravenous for arrhythmias: Loading dose 1 mg/kg, repeat 0.5-1 mg/kg if needed, then continuous infusion 20-50 mcg/kg/min. |
| Geriatric use | Lower initial doses recommended due to reduced hepatic blood flow and clearance. For local anesthesia, use lowest effective dose. For intravenous, start with lower end of dosing range (e.g., 0.5-1 mg/kg bolus) and monitor for toxicity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Beta-blockers may increase the risk of lidocaine toxicity Can cause CNS toxicity (seizures) and cardiovascular collapse.
| FDA category | Animal |
| Breastfeeding | Lidocaine is excreted into breast milk in small amounts (M/P ratio ~0.4). Oral bioavailability in infants is low. Typically compatible with breastfeeding; monitor infant for drowsiness or poor feeding if high maternal doses used. |
| Teratogenic Risk | FDA Pregnancy Category B. Lidocaine crosses placenta. No confirmed teratogenicity in human studies; epinephrine may reduce uteroplacental blood flow at high doses. First trimester: low risk; second/third trimester: neutral; peripartum: possible fetal bradycardia or acidosis at high doses. |
■ FDA Black Box Warning
Not for use in obstetrical paracervical block (severe fetal bradycardia and death). Do not inject into infected or inflamed tissues. Intravenous administration of lidocaine/epinephrine may cause severe hypertension, stroke, or death due to epinephrine.
| Common Effects | ventricular arrhythmias |
| Serious Effects |
Hypersensitivity to lidocaine, epinephrine, or amide-type anesthetics. Severe hypotension, complete heart block, cardiogenic shock (for lidocaine use in arrhythmias). Obstetrical paracervical block (absolute). Concurrent use of MAO inhibitors or tricyclic antidepressants (hypertensive crisis risk). Intravenous use of lidocaine with epinephrine (extreme caution only).
| Precautions | Risk of systemic toxicity (CNS and cardiovascular) from accidental intravascular injection; use lowest effective dose. Caution in patients with hepatic impairment, heart block, severe bradycardia, hypotension, hypovolemia, and with concomitant use of CYP1A2 or CYP3A4 inhibitors. Epinephrine may cause hypertension, tachycardia, and arrhythmias; avoid in patients with severe hypertension, hyperthyroidism, or pheochromocytoma. |
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| Fetal Monitoring | Monitor maternal blood pressure, heart rate, ECG, and signs of local anesthetic systemic toxicity (LAST). Fetal heart rate monitoring recommended during prolonged or high-dose administration. Assess for uterine hypertonus if epinephrine contraindicated. |
| Fertility Effects | No known adverse effects on fertility in humans. Animal studies show no impairment at clinically relevant doses. Epinephrine may affect uterine blood flow transiently; no evidence of long-term fertility impact. |