LIDOCAINE HYDROCHLORIDE 5% AND DEXTROSE 7.5%
Clinical safety rating: safe
Beta-blockers may increase the risk of lidocaine toxicity Can cause CNS toxicity (seizures) and cardiovascular collapse.
Lidocaine stabilizes the neuronal membrane by inhibiting sodium ion influx, thereby blocking the initiation and conduction of nerve impulses. Dextrose provides caloric support.
| Metabolism | Hepatic metabolism primarily by CYP1A2 and CYP3A4 to active metabolites monoethylglycinexylidide (MEGX) and glycinexylidide (GX) |
| Excretion | Renal excretion of unchanged lidocaine and metabolites; less than 10% excreted unchanged in urine. Hepatic metabolism produces active metabolites (MEGX, GX) which are renally excreted. Biliary/fecal excretion negligible. |
| Half-life | Terminal elimination half-life is approximately 1.5 to 2 hours in healthy adults after intravenous administration. In patients with heart failure or hepatic impairment, half-life may be prolonged to 4-6 hours or more. After epidural administration, half-life may be slightly longer due to ongoing absorption. |
| Protein binding | Approximately 65-75% bound to alpha-1-acid glycoprotein (AAG). Binding is concentration-dependent and saturable. In conditions with elevated AAG (e.g., inflammation, stress), binding increases. |
| Volume of Distribution | Volume of distribution at steady state is approximately 1.1 to 1.6 L/kg in healthy adults. Higher Vd indicates extensive tissue distribution, particularly to highly perfused organs (brain, heart, liver). Vd is increased in heart failure and decreased in hepatic disease. |
| Bioavailability | Intravenous: 100%. Epidural: Approximately 70-100% due to systemic absorption from epidural space. Subcutaneous/Intramuscular: 70-100% depending on site. Oral: Less than 35% due to extensive first-pass metabolism; not used orally for systemic effects. |
| Onset of Action | Intravenous: 30-90 seconds. Epidural: 5-15 minutes. Caudal/Peripheral nerve block: 5-15 minutes. Subcutaneous infiltration: Immediate to 2 minutes. |
| Duration of Action | Intravenous: 10-20 minutes (antiarrhythmic effect); absorption-dependent for local anesthesia. Epidural: 60-90 minutes (with epinephrine extends to 120-150 minutes). Peripheral nerve block: 60-120 minutes. Duration is dose-dependent and affected by vascularity of site. |
| Molecular Weight | 270.8 |
For IV administration, typical adult dose is 5-7 mg/kg intravenously as a single bolus, followed by 0.5-1 mg/kg every 5-10 minutes as needed, up to a maximum total dose of 200-300 mg. For epidural or caudal anesthesia, 15-20 mL of the 5% solution provides adequate block. For peripheral nerve block, 10-30 mL. Do not exceed 5 mg/kg per dose intravenously or 300 mg per dose by infiltration.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dosage adjustment is required for renal impairment. Lidocaine is minimally excreted renally (<10% unchanged), so GFR-based adjustments are not typically necessary. However, caution is advised in severe renal failure due to potential accumulation of metabolites. |
| Liver impairment | In Child-Pugh Class A (mild impairment): no adjustment needed. Child-Pugh Class B (moderate impairment): reduce dose by 50% and monitor for toxicity. Child-Pugh Class C (severe impairment): contraindicated or reduce dose by 75% with extreme caution; lidocaine clearance is significantly reduced. |
| Pediatric use | For IV administration: loading dose 1-2 mg/kg intravenously over 2-3 minutes, followed by infusion of 20-50 mcg/kg/min. For local anesthesia: maximum dose 4.5 mg/kg as a single injection. For epidural: 0.5-1 mg/kg per segment. Do not exceed 7 mg/kg total. |
| Geriatric use |
| 1st trimester | Lidocaine crosses the placenta. Use only if clearly needed. Risk of fetal bradycardia at high doses. |
| 2nd trimester | Use only if clearly needed. No known teratogenicity, but fetal bradycardia possible with high doses. |
| 3rd trimester | Use with caution near term; may cause neonatal CNS depression and bradycardia. |
Clinical note
Beta-blockers may increase the risk of lidocaine toxicity Can cause CNS toxicity (seizures) and cardiovascular collapse.
| FDA category | Animal |
| Placental transfer | Lidocaine rapidly crosses the placenta with a fetal/maternal ratio of approximately 0.5-0.7. |
| Breastfeeding |
■ FDA Black Box Warning
None
| Common Effects | ventricular arrhythmias |
| Serious Effects |
Hypersensitivity to lidocaine or any amide-type local anestheticSevere heart blockAdams-Stokes syndromeUncontrolled sinus bradycardiaMyasthenia gravis (relative, but caution)
| Precautions | Risk of cardiotoxicity including AV block, asystole, and hypotension, especially with high doses or rapid injection, Caution in patients with heart failure, hepatic impairment, or hypovolemia, Avoid intra-arterial injection, Monitor for CNS toxicity: dizziness, confusion, seizures |
| Food/Dietary | No significant food interactions. Avoid alcohol due to additive CNS depression. |
Loading safety data…
| Elderly patients may have reduced hepatic clearance and increased sensitivity. Use lower doses (e.g., 50-70% of adult dose) and titrate slowly. Monitor for cardiac and central nervous system toxicity. Maximum single dose should not exceed 200 mg for IV administration. |
| Lidocaine enters breast milk in small amounts. Oral bioavailability in infants is low; considered compatible with breastfeeding. Monitor for infant drowsiness. |
| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | Lidocaine hydrochloride is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, and there are no adequate and well-controlled studies in pregnant women. Use only if clearly needed. For lidocaine with dextrose, no specific teratogenic effects have been reported; however, high doses causing maternal toxicity may affect fetus. First trimester risk is low; second and third trimester risk is low with appropriate dosing. Paracervical block in obstetrics may cause fetal bradycardia; avoid excessive doses. |
| Fetal Monitoring | Monitor maternal vital signs, ECG, and CNS status (drowsiness, confusion, seizures) during administration. For epidural or regional use, monitor fetal heart rate for signs of distress, especially bradycardia. In obstetric anesthesia, assess uterine tone and fetal oxygenation. Monitor for signs of systemic toxicity (tinnitus, metallic taste, twitching). |
| Fertility Effects | No adequate studies on fertility in humans. In animals, lidocaine has not been shown to impair fertility. Dextrose does not affect reproductive function. Effects on male or female fertility are unlikely at therapeutic doses. |
| Clinical Pearls | This hyperbaric formulation (with dextrose) is intended for spinal anesthesia. Heavier than CSF, it ensures unilateral or saddle block distribution. Administer slowly to avoid high spinal. Monitor for hypotension and bradycardia. Maximum dose 50-100 mg for spinal anesthesia. |
| Patient Advice | You will receive numbing medicine into your lower back for surgery or procedures below the waist. · You may feel tingling or warmth in your legs as the medication takes effect. · Movement and sensation in your legs will temporarily be lost; do not attempt to get up until fully recovered. · Report any difficulty breathing, chest pain, or severe headache immediately. · Avoid alcohol for at least 24 hours after the procedure. |