XYLOCAINE DENTAL WITH EPINEPHRINE
Clinical safety rating: safe
Beta-blockers may antagonize cardiac effects and cause severe hypertension Can cause angina and arrhythmias in patients with heart disease.
Lidocaine blocks voltage-gated sodium channels (Nav1.5, Nav1.7, Nav1.8) in nerve cell membranes, inhibiting sodium influx and preventing depolarization and conduction of nerve impulses. Epinephrine acts as a local vasoconstrictor via alpha-1 adrenergic receptor agonism, reducing systemic absorption and prolonging anesthetic effect.
| Metabolism | Lidocaine: primarily hepatic via CYP1A2 (major) and CYP3A4 (minor) to monoethylglycinexylidide (MEGX) and glycinexylidide (GX), both active. Epinephrine: metabolized by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO) in the liver and other tissues. |
| Excretion | Lidocaine is primarily metabolized in the liver; less than 10% is excreted unchanged in urine. Metabolites are excreted renally. Biliary/fecal excretion is minimal. |
| Half-life | Terminal elimination half-life of lidocaine is approximately 1.5–2 hours in adults, but can be prolonged to 3–5 hours in patients with hepatic impairment or congestive heart failure. |
| Protein binding | Approximately 64–70% bound to alpha-1-acid glycoprotein and albumin. |
| Volume of Distribution | Vd = 1.1–1.7 L/kg. Higher Vd indicates extensive tissue distribution, particularly to highly perfused organs. |
| Bioavailability | Not applicable for injectable route; 100% bioavailability via infiltration or nerve block. |
| Onset of Action | Infiltration and nerve block: 2–5 minutes. |
| Duration of Action | Infiltration and nerve block: 60–120 minutes with epinephrine (1:100,000 or 1:200,000). Epinephrine prolongs duration and reduces systemic absorption. |
Dose range: 1.0–5.0 mL of 2% lidocaine with 1:100,000 epinephrine (20–100 mg lidocaine) injected locally. Maximum dose: 7 mg/kg lidocaine, not to exceed 500 mg total. Epinephrine component limits: 0.2 mg per visit (200 mcg). Repeat doses after 2–3 hours based on response.
| Dosage form | INJECTABLE |
| Renal impairment | No dosage adjustment necessary for lidocaine; monitor for toxicity in severe renal impairment (GFR < 30 mL/min) due to potential accumulation of metabolites. |
| Liver impairment | Child-Pugh Class B: reduce dose by 50%. Child-Pugh Class C: reduce dose by 75% or avoid use; monitor for lidocaine toxicity due to reduced metabolism. |
| Pediatric use | Weight-based dosing: Lidocaine 1.0–2.0 mg/kg per injection; maximum total dose 4.5 mg/kg (not to exceed 300 mg). Epinephrine maximum 0.01 mg/kg per visit (10 mcg/kg), not exceeding 0.2 mg. Reduce concentrations for smaller children (e.g., 1% lidocaine with 1:200,000 epinephrine). |
| Geriatric use | Use lower end of dose range due to reduced hepatic function and increased sensitivity. Maximum single dose: 4 mg/kg lidocaine (not to exceed 300 mg). Monitor for cardiovascular and CNS effects. Reduce doses of epinephrine in patients with cardiovascular disease. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Beta-blockers may antagonize cardiac effects and cause severe hypertension Can cause angina and arrhythmias in patients with heart disease.
| FDA category | Animal |
| Breastfeeding | Lidocaine is excreted into breast milk in small amounts (M/P ratio ~0.4). Epinephrine is rapidly metabolized and not detectable. The dose to infant is <4% of maternal weight-adjusted dose. Use with caution; monitor infant for irritability or poor feeding. |
| Teratogenic Risk |
■ FDA Black Box Warning
None
| Common Effects | cardiac arrest |
| Serious Effects |
Absolute: hypersensitivity to lidocaine, amide-type anesthetics, or epinephrine; severe hypotension; complete heart block (without pacemaker); allergy to sulfites (epinephrine may contain sulfite preservatives). Relative: severe hepatic disease; use with extreme caution in patients with pheochromocytoma, hypertension, hyperthyroidism, or unstable angina due to epinephrine; concurrent use of MAOIs or tricyclic antidepressants (increased risk of hypertensive crisis).
| Precautions | Risk of systemic toxicity (CNS depression, seizures, cardiac arrest) from accidental intravascular injection or overdose; use with caution in patients with hepatic impairment, severe renal disease, epilepsy, impaired cardiovascular function (e.g., bradycardia, hypotension, heart block), and those on beta-blockers, MAOIs, or tricyclic antidepressants (hypertensive crisis with epinephrine); avoid in areas of infection or inflammation; do not use with vasoconstrictors in fingers, toes, or nose due to risk of ischemia; monitor for methemoglobinemia (rare; more common with prilocaine). |
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| Lidocaine with epinephrine is Pregnancy Category B. Animal studies do not indicate fetal harm, but adequate human studies are lacking. Epinephrine at high doses may reduce uterine blood flow; use minimal doses. Risk during organogenesis (first trimester) is low but avoid unnecessary exposure. Third trimester: possible fetal bradycardia with high doses. |
| Fetal Monitoring | Monitor maternal vital signs (heart rate, blood pressure). Fetal heart rate monitoring if prolonged use or high doses. Watch for signs of local anesthetic toxicity (nervousness, dizziness, seizures). |
| Fertility Effects | No adverse effects on fertility reported in animal or human studies. Lidocaine does not affect sperm or oocyte function at clinical doses. |