CITANEST
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CITANEST (CITANEST).
Local anesthetic that blocks sodium channels in nerve cell membranes, inhibiting depolarization and propagation of action potentials, resulting in reversible loss of sensation.
| Metabolism | Primarily metabolized in the liver via amidases to ortho-toluidine and other metabolites. Ortho-toluidine is further metabolized and may contribute to methemoglobin formation. |
| Excretion | Primarily hepatic metabolism; less than 5% excreted unchanged in urine. Metabolites are excreted renally. Biliary/fecal excretion is minimal. |
| Half-life | Terminal elimination half-life approximately 1.5-2 hours in adults; prolonged in hepatic impairment or neonates. |
| Protein binding | Approximately 55% bound, primarily to alpha-1-acid glycoprotein and albumin. |
| Volume of Distribution | Vd approximately 1.0-1.5 L/kg; extensive tissue distribution, reflecting rapid uptake into well-perfused organs. |
| Bioavailability | Intravenous: 100%; Oral: negligible due to extensive first-pass metabolism; topical: minimal systemic absorption unless applied to broken skin or mucous membranes. |
| Onset of Action | Infiltration: 2-5 minutes; Epidural: 5-15 minutes; Nerve block: 10-20 minutes. |
| Duration of Action | Infiltration: 30-60 minutes (with epinephrine up to 120 minutes); Epidural: 30-60 minutes; Nerve block: 45-90 minutes. Shorter duration without epinephrine. |
Local anesthesia: 2-4 mL of 1% or 2% solution without epinephrine, maximum 5 mg/kg (300 mg for adults). Intravenous regional anesthesia: 0.5% solution, 40-60 mL, maximum 300 mg. Epidural: 1.5% solution, 15-20 mL, maximum 300 mg. Subarachnoid: 5% solution with glucose, 80-100 mg. Maximum total dose: 600 mg with epinephrine, 400 mg without epinephrine.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment guidelines for renal impairment. Use with caution; monitor for prolonged anesthetic effect and systemic toxicity. |
| Liver impairment | Contraindicated in severe hepatic disease (Child-Pugh class C). For mild to moderate impairment (Child-Pugh A/B), reduce dose by 50% and monitor for signs of toxicity. |
| Pediatric use | Local infiltration: 0.5-2.5 mg/kg (maximum 5 mg/kg) of 0.5% or 1% solution. Caudal epidural: 1-1.5 mL/kg of 0.5% solution (maximum 40 mL). Total dose not to exceed 5 mg/kg. |
| Geriatric use | Reduce dose by 40% due to increased risk of systemic toxicity and prolonged effect. Use lower concentrations and volumes, and consider epinephrine to reduce absorption. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CITANEST (CITANEST).
| Breastfeeding | Prilocaine is excreted into breast milk in low amounts (<2% of maternal dose). The milk-to-plasma ratio is approximately 0.5. At usual clinical doses, it is considered compatible with breastfeeding. However, caution is advised with repeated high doses due to potential for methemoglobinemia in the infant. Monitor for signs of cyanosis or lethargy. |
| Teratogenic Risk | Citanest (prilocaine) crosses the placenta. Animal studies have not demonstrated teratogenicity. In humans, no well-controlled studies exist; however, use in the first trimester is generally avoided unless clearly needed. During the second and third trimesters, lidocaine-type local anesthetics are considered relatively safe in standard doses. High doses or prolonged use may cause fetal bradycardia or CNS depression. |
■ FDA Black Box Warning
There is no FDA black box warning for Citanest (prilocaine) as of the latest data. However, use in neonates and infants may be associated with methemoglobinemia.
| Serious Effects |
["Hypersensitivity to prilocaine or any amide-type local anesthetic","Severe liver disease","Severe hypertension","Myasthenia gravis (relative contraindication)","Neonates and infants (due to risk of methemoglobinemia)","Patients with known glucose-6-phosphate dehydrogenase deficiency"]
| Precautions | ["Risk of methemoglobinemia, especially in neonates, infants, and patients with glucose-6-phosphate dehydrogenase deficiency","Avoid use in patients with severe liver disease","Caution in patients with cardiac disease, especially arrhythmias","Monitor for signs of central nervous system or cardiac toxicity with large doses","Not recommended for use in pregnant women during labor and delivery (may cause fetal bradycardia)","May cause allergic reactions in patients with hypersensitivity to amide-type anesthetics"] |
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| Fetal Monitoring | Monitor maternal vital signs (heart rate, blood pressure, oxygen saturation) during and after administration. Observe for signs of local anesthetic systemic toxicity (LAST): perioral numbness, tinnitus, seizures, cardiac arrhythmias. Monitor fetal heart rate pattern if used during labor; fetal bradycardia may occur. In prolonged infusions or high doses, check maternal and fetal methemoglobin levels if >3 g cumulative dose. |
| Fertility Effects | No specific fertility studies with prilocaine in humans. Animal studies show no impairment of fertility at doses up to 30 mg/kg. Local anesthetics generally do not affect fertility when used as directed. |