LIDOCAINE HYDROCHLORIDE IN PLASTIC CONTAINER
Clinical safety rating: safe
Beta-blockers may increase the risk of lidocaine toxicity Can cause CNS toxicity (seizures) and cardiovascular collapse.
Blocks voltage-gated sodium channels, inhibiting action potential propagation in neurons and cardiac myocytes.
| Metabolism | Primarily hepatic via CYP1A2 and CYP3A4; major metabolite monoethylglycinexylidide (MEGX) and glycinexylidide (GX). |
| Excretion | Renal excretion of unchanged drug and metabolites: ~90% as metabolites (e.g., monoethylglycinexylidide, glycinexylidide), <10% unchanged. Biliary/fecal: minimal (<1%). |
| Half-life | Terminal elimination half-life: 1.5–2 hours (single dose); prolonged to 2–3 hours with repeated dosing or in heart failure, liver disease, or elderly. Context: Effective for 1–2 hours after IV bolus, requiring infusion for sustained effect. |
| Protein binding | 70% bound primarily to alpha-1-acid glycoprotein; binding decreases in renal disease and increases in inflammatory states. |
| Volume of Distribution | Vd: 1.1–1.6 L/kg. Clinically, large Vd indicates extensive tissue distribution; increased in heart failure (Vd reduced) due to decreased perfusion. |
| Bioavailability | Oral: <35% due to extensive first-pass metabolism; IM: 80–90%; Rectal: ~70%; Epidural/Topical: negligible systemic bioavailability unless applied to large areas or damaged skin. |
| Onset of Action | IV: 45–90 seconds (antiarrhythmic effect); IM: 5–15 minutes; Epidural: 5–15 minutes; Topical: 3–5 minutes (anesthesia). |
| Duration of Action | IV bolus: 10–20 minutes (antiarrhythmic); IV infusion: titrated to effect; Epidural: 60–90 minutes with epinephrine, 30–60 minutes without; Topical: 30–60 minutes. Note: Duration can be extended by adding epinephrine or by repeated administration. |
1-1.5 mg/kg IV bolus, then 0.5-0.75 mg/kg IV bolus every 5-10 min to a max of 3 mg/kg total loading dose; maintenance infusion 1-4 mg/min IV. For epidural: 5-10 mL of 1-2% solution.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for GFR >30 mL/min; for GFR <30 mL/min, use with caution and reduce maintenance infusion by 50%. |
| Liver impairment | Child-Pugh A: reduce loading dose by 50%; Child-Pugh B: reduce loading dose by 50% and maintenance infusion by 50%; Child-Pugh C: contraindicated or use with extreme caution with 75% reduction. |
| Pediatric use | Loading dose: 1 mg/kg IV bolus; maintenance infusion: 20-50 mcg/kg/min IV. For epidural: 1-1.5 mg/kg of 1% solution. |
| Geriatric use | Reduce loading dose by 50% and maintenance infusion by 50% due to decreased clearance and increased risk of 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; the milk-to-plasma (M/P) ratio is approximately 0.4. The relative infant dose is estimated to be 2-3% of the maternal weight-adjusted dose, which is considered compatible with breastfeeding. However, caution is advised with high maternal doses or long-term use due to potential accumulation. Monitor infant for signs of lidocaine toxicity (e.g., drowsiness, poor feeding). |
| Teratogenic Risk |
■ FDA Black Box Warning
Not for intravenous injection into digitalis-induced toxicity or severe heart block; risk of cardiac arrest.
| Common Effects | ventricular arrhythmias |
| Serious Effects |
Hypersensitivity to lidocaine or amide anesthetics; severe heart block (without pacemaker); Stokes-Adams syndrome; Wolff-Parkinson-White syndrome; untreated sinus bradycardia; severe hypotension; hypovolemia; myasthenia gravis (relative).
| Precautions | Risk of systemic toxicity (CNS depression, seizures, cardiac arrhythmias); use lowest effective dose; monitor for toxicity in hepatic impairment, heart failure, elderly; avoid intravascular injection. |
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| Lidocaine hydrochloride is classified as FDA Pregnancy Category B. Animal reproduction studies have not demonstrated fetal risk, but there are no adequate and well-controlled studies in pregnant women. Lidocaine crosses the placenta, but fetal concentrations are lower than maternal. Use during the first trimester only if clearly needed. During second and third trimesters, lidocaine has been used for obstetrical analgesia/anesthesia without significant teratogenic effects. However, high doses or prolonged use may produce fetal bradycardia, acidosis, and neurobehavioral effects. Avoid paracervical block in preterm labor due to risk of fetal bradycardia. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and oxygen saturation during administration. Assess for signs of systemic toxicity (perioral numbness, tinnitus, metallic taste, seizures). Fetal heart rate monitoring is recommended, especially during paracervical block or epidural use, as lidocaine can cause fetal bradycardia. Neonatal monitoring for neurobehavioral depression if high doses used near delivery. |
| Fertility Effects | No known adverse effects on fertility in animal studies or human data. Lidocaine is not associated with impaired reproductive capacity. No specific studies on fertility in humans, but systemic absorption during local use is minimal and unlikely to affect fertility. |