XYLOCAINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for XYLOCAINE (XYLOCAINE).
Lidocaine binds to and inhibits voltage-gated sodium channels in the neuronal membrane, stabilizing the membrane and preventing the initiation and conduction of nerve impulses, thereby producing local anesthesia.
| Metabolism | Primarily hepatic via CYP1A2 and CYP3A4 to active metabolites (monoethylglycinexylidide and glycinexylidide). |
| Excretion | Hepatic metabolism (primarily by CYP1A2 and CYP3A4) to metabolites, mainly monoethylglycinexylidide (MEGX) and glycinexylidide (GX); less than 10% excreted unchanged in urine. Renal excretion of metabolites: MEGX (70-80%) and GX (10-20%). Biliary/fecal elimination is minimal. |
| Half-life | Terminal elimination half-life is approximately 1.5 to 2 hours in adults, prolonged to 2-3 hours in patients with hepatic impairment, and may exceed 5 hours in neonates or patients with heart failure. |
| Protein binding | Approximately 65-70% bound to plasma proteins, primarily alpha-1-acid glycoprotein (AAG) and, to a lesser extent, albumin. |
| Volume of Distribution | Volume of distribution (Vd) is 0.8-1.3 L/kg. Higher Vd in neonates (up to 2.75 L/kg) indicates extensive tissue distribution. |
| Bioavailability | Intravenous: 100%; Intramuscular: 70-90%; Epidural: near 100%; Topical: variable and low due to systemic absorption, typically <10%; Oral: less than 30% due to extensive first-pass metabolism. |
| Onset of Action | Intravenous: 45-90 seconds; Intramuscular (injectable): 5-15 minutes; Topical (mucous membrane): 2-5 minutes; Epidural: 10-15 minutes. |
| Duration of Action | Intravenous: 10-20 minutes (anesthetic effect); Infiltration: 0.5-2 hours (dependent on epinephrine co-administration); Epidural: 1-2 hours. Duration is prolonged with addition of epinephrine. |
| Action Class | Local anaesthetic (Amides) |
| Brand Substitutes | Resocaine 2% Injection, Biocaine 2% Injection, Ligopil 2% Injection, Anescaine 2% Injection, Xylonumb 2% Injection, Lox 5% Ointment, Lidovac Ointment, Xylo Ointment, Gesicain Ointment, Xylo 4% Injection, Lox 4% Injection, Oculan 1% Injection, Lignox 1% Injection, Ocu Ligno 1% Injection, Xylocaine Heavy 5% Injection, Lox Heavy 5% Injection, Xynova 5% Injection, Anescaine 5% Injection |
1-5 mg/kg (max 300 mg) local infiltration; epidural: 1-2% solution, 5-20 mL.
| Dosage form | OINTMENT |
| Renal impairment | No adjustment required for GFR >30 mL/min; avoid in severe renal impairment (GFR <30 mL/min) due to risk of accumulation. |
| Liver impairment | Child-Pugh A/B: reduce dose by 50%; Child-Pugh C: contraindicated. |
| Pediatric use | 1-2 mg/kg (max 4.5 mg/kg) local infiltration; adjust based on lean body weight. |
| Geriatric use | Reduce dose by 40-50% due to decreased clearance and increased sensitivity to CNS/cardiac effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for XYLOCAINE (XYLOCAINE).
| Breastfeeding | Excreted into breast milk in low amounts (M/P ratio approximately 1.0). Considered compatible with breastfeeding; monitor for signs of local anesthetic toxicity in infant. |
| Teratogenic Risk | First trimester: No increased risk of major malformations observed in human studies. Second and third trimesters: Potential for fetal bradycardia and central nervous system depression with high maternal serum levels. Use only if clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to lidocaine or amide-type local anesthetics","Stokes-Adams syndrome or severe heart block (for IV antiarrhythmic use)","Severe hypotension or cardiogenic shock","Do not use for spinal anesthesia if patient has bleeding disorders or infection at injection site"]
| Precautions | ["Risk of local anesthetic systemic toxicity (LAST) including CNS and cardiovascular effects, especially with inadvertent intravascular injection or high doses","Use with caution in patients with hepatic impairment, severe renal impairment, or hypovolemia","May cause methemoglobinemia, especially in infants","Monitor ECG when used intravenously for arrhythmias"] |
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| Continuous fetal heart rate monitoring during continuous infusion or high-dose administration. Monitor maternal vital signs, ECG, and neurological status for toxicity. |
| Fertility Effects | No evidence of impaired fertility in animal studies. Clinical data on human fertility effects are lacking; unlikely to cause reproductive impairment at therapeutic doses. |