LIDOCAINE HYDROCHLORIDE 0.4% IN DEXTROSE 5%
Clinical safety rating: safe
Beta-blockers may increase the risk of lidocaine toxicity Can cause CNS toxicity (seizures) and cardiovascular collapse.
Lidocaine is a class IB antiarrhythmic agent that blocks voltage-gated sodium channels, inhibiting phase 0 depolarization and decreasing automaticity in ventricular myocardial cells. It also has local anesthetic properties by blocking nerve impulse conduction.
| Metabolism | Hepatically metabolized primarily by cytochrome P450 1A2 (CYP1A2) to monoethylglycinexylidide (MEGX) and glycinexylidide (GX), both active metabolites. |
| Excretion | Renal excretion of metabolites (primarily monoethylglycinexylidide and glycinexylidide) accounts for >90% of elimination. Less than 10% excreted unchanged in urine. Biliary/fecal excretion is negligible. |
| Half-life | Terminal elimination half-life is approximately 1.5-2 hours (mean 1.8 h) in healthy adults. In patients with hepatic impairment or heart failure, half-life may be prolonged to >3 hours. In neonates, half-life can be 3-6 hours. |
| Protein binding | 70% bound primarily to alpha-1-acid glycoprotein (AAG), with some binding to albumin. Binding is concentration-dependent and decreases in conditions with low AAG (e.g., neonates) or high free fatty acids. |
| Volume of Distribution | Volume of distribution at steady state (Vdss) is approximately 1.1-1.6 L/kg in adults. Higher Vd (up to 2-3 L/kg) in neonates. Vd is increased in patients with hepatic cirrhosis or heart failure. |
| Bioavailability | Intravenous: 100% (by definition). Intramuscular: approximately 100%. Oral: <35% due to extensive first-pass metabolism. Not administered orally for systemic effect; only as topical or local anesthetic. |
| Onset of Action | Intravenous: 45-90 seconds; Intramuscular: 5-15 minutes; Subcutaneous infiltration: 2-5 minutes. Epidural: 5-15 minutes. |
| Duration of Action | Intravenous bolus: 10-20 minutes; Continuous IV infusion: duration depends on infusion rate; Intramuscular: 60-90 minutes; Subcutaneous infiltration: 30-60 minutes; Epidural: 60-90 minutes. Duration may be prolonged in patients with hepatic or cardiac disease. |
Intravenous infusion: 1-4 mg/min (0.25-1 mL/min of 0.4% solution) after a loading dose of 1-1.5 mg/kg IV bolus for ventricular arrhythmias. Maximum total dose: 3 mg/kg.
| Dosage form | INJECTABLE |
| Renal impairment | GFR 10-50 mL/min: No adjustment needed. GFR <10 mL/min: Reduce infusion rate by 50% due to metabolite accumulation. |
| Liver impairment | Child-Pugh class A: No adjustment. Child-Pugh class B: Reduce infusion rate by 50%. Child-Pugh class C: Avoid use or reduce infusion rate by 75% with monitoring. |
| Pediatric use | Neonates: Loading dose 1 mg/kg IV, infusion 20-50 mcg/kg/min. Children: Loading dose 1 mg/kg IV, infusion 20-50 mcg/kg/min. Maximum dose: 5 mg/kg total. |
| Geriatric use | Reduce infusion rate by 25-50% due to decreased clearance and increased risk of toxicity. Use lower loading doses. |
| 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 approximately 0.4-0.8. The relative infant dose is <4% of maternal weight-adjusted dose. Considered compatible with breastfeeding; monitor infant for drowsiness or feeding difficulties. |
| Teratogenic Risk | Lidocaine crosses the placenta. First trimester: No well-controlled studies, but animal studies show no teratogenicity at clinically relevant doses. Second trimester: No known elevated risk of major malformations. Third trimester: Use in paracervical block can cause fetal bradycardia and acidosis. Avoid near term for obstetric anesthesia due to potential neonatal depression. |
■ FDA Black Box Warning
Not available (no FDA boxed warning for lidocaine hydrochloride 0.4% in dextrose 5%).
| Common Effects | ventricular arrhythmias |
| Serious Effects |
["History of hypersensitivity to lidocaine or amide-type anesthetics","Stokes-Adams syndrome","Wolff-Parkinson-White syndrome (unless pacing is available)","Severe heart block (unless a pacemaker is in place)"]
| Precautions | ["Cardiotoxicity: Risk of cardiac arrest, hypotension, bradycardia, and arrhythmias, especially with high doses or rapid administration","Central nervous system toxicity: Seizures, respiratory depression, and altered mental status","Use with caution in patients with hepatic impairment, heart failure, or elderly patients due to reduced clearance","Monitor for lidocaine toxicity (e.g., drowsiness, paresthesias, muscle twitching)"] |
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| Fetal Monitoring | Continuous fetal heart rate monitoring during labor; maternal ECG for signs of systemic toxicity (e.g., QRS widening, arrhythmias); monitor maternal blood pressure and levels of consciousness. In prolonged infusion, monitor lidocaine levels (therapeutic 1.5-5 mcg/mL). |
| Fertility Effects | No evidence of adverse effects on fertility in animal studies or human data. Lidocaine does not impair spermatogenesis or oocyte maturation at clinical concentrations. |