XYLOCAINE DENTAL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for XYLOCAINE DENTAL (XYLOCAINE DENTAL).
Lidocaine is an amide-type local anesthetic that stabilizes the neuronal membrane by inhibiting sodium ion influx, thereby blocking the initiation and conduction of nerve impulses.
| Metabolism | Primarily hepatic via CYP1A2 and CYP3A4; major metabolite is monoethylglycinexylidide (MEGX), followed by glycinexylidide (GX). |
| Excretion | Renal excretion of unchanged drug and metabolites accounts for >95% of the dose. Approximately 70% is excreted as the metabolite 4-hydroxy-2,6-xylidine; less than 10% is unchanged lidocaine. Biliary/fecal excretion is minimal (<5%). |
| Half-life | 1.5–2 hours in adults with normal hepatic function. Prolonged to 2–3 hours in patients with hepatic impairment or congestive heart failure; may exceed 5 hours in severe hepatic disease. |
| Protein binding | Approximately 60–80% bound to alpha-1-acid glycoprotein (AAG). Binding is concentration-dependent and saturable. |
| Volume of Distribution | 1.1–1.7 L/kg in adults. Higher Vd (>2 L/kg) in patients with cardiac failure or hepatic disease due to reduced clearance. |
| Bioavailability | Oral bioavailability is approximately 35% due to extensive first-pass hepatic metabolism. Not administered orally clinically; intravenous bioavailability is 100%. |
| Onset of Action | Infiltration: 2–5 minutes. Nerve block: 5–10 minutes. Onset is faster with epinephrine-containing formulations due to vasoconstriction. |
| Duration of Action | Infiltration without epinephrine: 30–60 minutes. With epinephrine (1:100,000): 60–120 minutes for soft tissue anesthesia; 90–180 minutes for pulpal anesthesia. Duration is shorter in highly vascular areas. |
Xylocaine Dental (lidocaine HCl 2% with epinephrine 1:100,000 or 1:50,000): For infiltration/inferior alveolar nerve block, maximum dose 3.4 mg/kg (4.5 mg/kg with epinephrine 1:100,000) not to exceed 300 mg; usual adult dose: 1–5 mL (20–100 mg) administered via oral submucosal injection.
| Dosage form | INJECTABLE |
| Renal impairment | No adjustment required for standard dosing; however, caution in severe renal impairment (eGFR <30 mL/min) due to potential accumulation of metabolites (MEGX, GX); use reduced doses and monitor for toxicity. |
| Liver impairment | In Child-Pugh class B or C, reduce dose by 50% due to decreased clearance; avoid in severe hepatic impairment unless benefits outweigh risks; monitor for signs of CNS toxicity. |
| Pediatric use | Weight-based dosing: maximum 4.5 mg/kg with epinephrine 1:100,000 (absolute max 300 mg). Example: For 20 kg child, max dose = 90 mg (4.5 mL of 2% solution). Dose volume adjusted to achieve adequate anesthesia. |
| Geriatric use | Elderly patients may have reduced hepatic clearance; use lowest effective dose and limit total dose to 200 mg (10 mL of 2% solution) with epinephrine; monitor for prolonged effect and cardiovascular changes. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for XYLOCAINE DENTAL (XYLOCAINE DENTAL).
| Breastfeeding | Lidocaine is excreted into breast milk in low amounts (M/P ratio ~0.4). Relative infant dose is estimated <2% of maternal weight-adjusted dose. Considered compatible with breastfeeding, but observe infant for drowsiness or feeding difficulties. |
| Teratogenic Risk | Lidocaine (Xylocaine) crosses the placenta. First trimester: No evidence of major malformations from human data, but risk cannot be excluded. Second/third trimesters: Use as dental anesthetic is considered low risk; no increased teratogenicity reported. Continuous infusion or high doses may cause fetal bradycardia or acidosis. |
■ FDA Black Box Warning
Not applicable (no FDA black box warning for Xylocaine Dental).
| Serious Effects |
["Hypersensitivity to lidocaine or other amide anesthetics","Severe hypotension","Complete heart block","Patients with porphyria"]
| Precautions | ["Risk of systemic toxicity if injected intravascularly or overdosed","Use with caution in patients with hepatic impairment, severe renal impairment, or cardiac disease","Avoid use in patients with myasthenia gravis or pseudocholinesterase deficiency","Methemoglobinemia risk with high doses or concurrent use of oxidizing agents"] |
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| Fetal Monitoring | Standard maternal vital signs; fetal heart rate monitoring if used peripartum or with large doses. No specific fetal surveillance required for routine dental anesthesia. |
| Fertility Effects | No evidence of impaired fertility in animal studies or human reports. |