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. |
| Molecular Weight | Lidocaine: 234.34 Da; Epinephrine: 183.20 Da |
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 | Lidocaine with epinephrine is generally considered safe during the first trimester when used in minimal effective doses. However, epinephrine may theoretically reduce uterine blood flow; use only if clearly needed. |
| 2nd trimester | Safe in the second trimester with standard dosing. Avoid intravascular injection to minimize systemic effects. |
| 3rd trimester | Generally safe, but closer to term, lidocaine may accumulate in fetal tissues. Use lowest effective dose. Epinephrine may cause uterine vasoconstriction; avoid in cases of preeclampsia or hypertension. |
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 |
| Placental transfer | Lidocaine crosses the placenta by passive diffusion. Fetal/maternal ratio is approximately 0.5-0.7. Protein binding limits transfer (lidocaine 64-76% bound; epinephrine not significantly transferred). |
■ FDA Black Box Warning
None
| Common Effects | cardiac arrest |
| Serious Effects |
Hypersensitivity to lidocaine, epinephrine, or amide-type anestheticsSevere hypertension (uncontrolled)Severe coronary artery diseaseConcurrent use of monoamine oxidase inhibitors (MAOIs) or tricyclic antidepressants (TCAs) in high doses (risk of hypertensive crisis)Cocaine useSulfite allergy (if product contains sulfites)
| 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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| Breastfeeding | Lidocaine is excreted into breast milk in minimal amounts (estimated infant dose <4% of maternal weight-adjusted dose). Epinephrine is not orally bioavailable. Therefore, use is considered compatible with breastfeeding following dental procedures. Observe infant for any signs of sedation or allergic reaction. |
| Lactation Rating | L2 - Safer |
| Teratogenic Risk | 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. |
| Food/Dietary | No significant food interactions. Avoid hot foods or beverages until anesthesia resolves to prevent burns. |
| Clinical Pearls | Limit total lidocaine dose to 7 mg/kg with epinephrine; aspirate to avoid intravascular injection; avoid use in patients with severe hepatic disease or pseudocholinesterase deficiency; monitor for CNS toxicity (perioral numbness, metallic taste, seizures) and cardiac toxicity (bradycardia, hypotension). |
| Patient Advice | You may experience temporary numbness of the tongue, lips, or face after the injection. · Avoid eating or drinking until numbness has completely worn off to prevent biting your tongue or cheek. · Do not chew gum or eat hard foods while numb. · Contact your dentist if numbness persists beyond expected duration (typically 2-4 hours). · Inform your dentist if you have a history of heart disease, liver disease, or allergy to local anesthetics. |