LIGNOSPAN FORTE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LIGNOSPAN FORTE (LIGNOSPAN FORTE).
Lidocaine and prilocaine stabilize neuronal membranes by inhibiting sodium ion influx, thereby blocking initiation and conduction of nerve impulses.
| Metabolism | Lidocaine: Hepatic metabolism via CYP1A2 and CYP3A4 to active metabolites; prilocaine: Hepatic metabolism to o-toluidine and other metabolites. |
| Excretion | Renal excretion of metabolites (predominantly 4-hydroxy-2,6-xylidine and other conjugates): ~90%; biliary/fecal: <10% as unchanged drug. |
| Half-life | Terminal elimination half-life of lidocaine: 1.5–2 hours; in hepatic impairment or heart failure, may extend to >4 hours. For the vasoconstrictor (epinephrine), half-life is approximately 2 minutes due to rapid uptake and metabolism. |
| Protein binding | Lidocaine: ~65–75% bound to alpha-1-acid glycoprotein and albumin; epinephrine: ~50–60% bound to plasma proteins (mainly albumin). |
| Volume of Distribution | Lidocaine: Vd ~1.1–1.7 L/kg, indicating extensive tissue distribution; epinephrine: Vd ~0.5–1.0 L/kg (large for a catecholamine). |
| Bioavailability | Oral: <30% (extensive first-pass metabolism); intramuscular: ~100% (rapid absorption); subcutaneous infiltration: 100% (local effect); intravenous: 100%. |
| Onset of Action | Infiltration: 1–5 minutes; dental block (mandibular): 2–5 minutes; epidural: 5–15 minutes. |
| Duration of Action | Infiltration with epinephrine: 60–120 minutes; dental block with epinephrine: 120–180 minutes; epidural with epinephrine: 90–150 minutes. Prolonged by epinephrine due to vasoconstriction. |
Adults: 2% lidocaine with 1:100,000 epinephrine, max 7 mg/kg lidocaine (500 mg) without epinephrine or 4.5 mg/kg (300 mg) with epinephrine; for dental infiltration or nerve block, 1-2 mL per site.
| Dosage form | INJECTABLE |
| Renal impairment | No specific adjustment required; lidocaine is hepatically metabolized; use caution in severe renal impairment (CrCl <30 mL/min) due to potential accumulation of metabolites. |
| Liver impairment | Avoid in severe hepatic impairment (Child-Pugh class C); for moderate impairment (Child-Pugh B), reduce dose by 50% and monitor for toxicity. |
| Pediatric use | Weight-based: 1-2 mg/kg lidocaine (max 4.5 mg/kg with epinephrine) per infiltration; do not exceed 4.5 mg/kg total dose. |
| Geriatric use | Reduce dose by 50% due to decreased hepatic clearance and increased sensitivity; monitor for CNS and cardiovascular effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for LIGNOSPAN FORTE (LIGNOSPAN FORTE).
| Breastfeeding | Small amounts of lidocaine are excreted into breast milk. The milk-to-plasma (M/P) ratio is approximately 0.3-1.0. The relative infant dose is estimated at <5% of maternal weight-adjusted dose, considered safe during breastfeeding. Epinephrine is not significantly excreted due to rapid metabolism. Use of Lignospan Forte is compatible with breastfeeding; however, monitor for infant sedation or irritability with prolonged use. |
| Teratogenic Risk | Lignospan Forte (lidocaine 2% with epinephrine 1:100,000) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated teratogenic effects at doses up to 6 times the human dose. However, no adequate and well-controlled studies exist in pregnant women. Lidocaine crosses the placenta. In the first trimester, risk is minimal but should be used only if clearly needed. In second and third trimesters, no known fetal harm at standard doses, but epinephrine may reduce uterine blood flow; use lowest effective dose and avoid intra-arterial injection. Avoid in preeclampsia or uteroplacental insufficiency. There is a theoretical risk of fetal bradycardia with high plasma levels. |
■ FDA Black Box Warning
Methemoglobinemia: Cases of methemoglobinemia have been reported, especially in infants and children. Use with caution in patients with glucose-6-phosphate dehydrogenase deficiency, congenital or idiopathic methemoglobinemia, or concurrent use with oxidizing agents.
| Serious Effects |
Hypersensitivity to amide-type local anesthetics; severe hepatic impairment; known history of methemoglobinemia; use in children under 3 years of age for certain formulations.
| Precautions | Risk of methemoglobinemia, especially in children <6 months; avoid use in patients with severe hepatic impairment; use caution with concurrent use of Class III antiarrhythmics; monitor for signs of systemic toxicity. |
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| Fetal Monitoring | Monitor maternal vital signs (blood pressure, heart rate) and fetal heart rate during administration, especially with large volumes or in high-risk pregnancies. Observe for signs of local anesthetic systemic toxicity (LAST): perioral numbness, metallic taste, tinnitus, seizures, arrhythmias. In obstetrics, avoid paracervical block as it may cause fetal bradycardia. Continuous fetal monitoring recommended during labor and delivery. |
| Fertility Effects | No evidence that lidocaine or epinephrine adversely affects human fertility. Animal studies have not shown impaired fertility at clinically relevant doses. Local anesthetics used for dental procedures are unlikely to impact reproductive function. |