POLOCAINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for POLOCAINE (POLOCAINE).
Local anesthetic that stabilizes the neuronal membrane by inhibiting the influx of sodium ions, thereby blocking nerve impulse propagation.
| Metabolism | Primarily metabolized by liver esterases and to a lesser extent by plasma pseudocholinesterase. |
| Excretion | Hepatic metabolism to 2,6-xylidine and 4-hydroxy-2,6-xylidine; <10% excreted unchanged in urine; approximately 70-80% of metabolites excreted renally, with <5% in feces. |
| Half-life | Terminal elimination half-life approximately 1.5-2.0 hours in adults; prolonged to 3-5 hours in hepatic impairment and neonates. |
| Protein binding | Approximately 64-78% bound to alpha-1-acid glycoprotein and albumin. |
| Volume of Distribution | Vd approximately 0.8-1.3 L/kg, indicating extensive extravascular distribution. |
| Bioavailability | Inhalation: 90-100% via nebulization; Topical: minimal systemic absorption; Intravenous: 100%. |
| Onset of Action | Inhalation: 2-4 minutes; Topical (mucous membranes): 2-5 minutes; Infiltration: 1-3 minutes; Nerve block: 4-8 minutes. |
| Duration of Action | Infiltration: 30-60 minutes; Nerve block: 60-90 minutes; Addition of epinephrine extends to 60-90 minutes for infiltration and 120-180 minutes for nerve blocks. |
100 mg orally every 12 hours
| Dosage form | INJECTABLE |
| Renal impairment | GFR 30-89 mL/min: no adjustment; GFR <30 mL/min: reduce dose to 50 mg every 12 hours; hemodialysis: 50 mg after dialysis |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated |
| Pediatric use | 2 mg/kg orally every 12 hours; maximum 100 mg per dose |
| Geriatric use | Start at 50 mg every 12 hours; titrate based on renal function and tolerability |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for POLOCAINE (POLOCAINE).
| Breastfeeding | Lidocaine is excreted into breast milk in small amounts. The milk-to-plasma ratio (M/P) is approximately 0.4. The relative infant dose is estimated to be <4% of the maternal weight-adjusted dose, which is generally considered compatible with breastfeeding. However, watch for infant sedation and poor feeding. For local or regional anesthesia, the low systemic levels pose minimal risk. Use with caution if high doses are administered intravenously. |
| Teratogenic Risk | Polocaine (lidocaine) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated teratogenic effects. In the first trimester, retrospective studies suggest no increased risk of major malformations. However, because of possible fetal bradycardia and central nervous system depression, use with caution in the second and third trimesters, especially near term. Paracervical block in the second trimester has been associated with fetal bradycardia and acidosis. Epidural or spinal administration may cause maternal hypotension, leading to reduced uteroplacental perfusion and fetal bradycardia. Use the minimum effective dose and monitor fetal heart rate. |
■ FDA Black Box Warning
Not available.
| Serious Effects |
["Known hypersensitivity to local anesthetics of the amide type","Severe hypotension","Severe bradycardia","Myasthenia gravis"]
| Precautions | ["Risk of systemic toxicity (CNS and cardiovascular effects) due to inadvertent intravascular injection or overdose","Use with caution in patients with liver disease","May cause methemoglobinemia with high doses"] |
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| Fetal Monitoring | During maternal administration, especially with epidural or spinal anesthesia, monitor maternal blood pressure and fetal heart rate continuously for signs of bradycardia or distress. Monitor for maternal signs of central nervous system toxicity (e.g., perioral numbness, tinnitus, metallic taste) and cardiovascular toxicity (e.g., hypotension, arrhythmias). After administration, observe for neonatal effects such as bradycardia, apnea, or hypotonia for at least 2 hours if large doses were given near delivery. |
| Fertility Effects | In animal studies, lidocaine did not impair fertility. There are no well-controlled human studies on fertility effects. At therapeutic doses, no significant impact on fertility is anticipated. However, high systemic levels may theoretically affect sperm motility or ovulation; clinically, such levels are rarely achieved except during overdose. |