CITANEST FORTE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CITANEST FORTE (CITANEST FORTE).
Prilocaine (CITANEST FORTE) is a local anesthetic that blocks sodium ion channels in nerve cell membranes, thereby inhibiting the initiation and conduction of nerve impulses.
| Metabolism | Primarily metabolized by the liver via amide hydrolysis; prilocaine is metabolized by amidases, producing o-toluidine metabolites that can cause methemoglobinemia. |
| Excretion | Renal: 90-95% as metabolites and unchanged drug (prilocaine); biliary/fecal: <5%. |
| Half-life | Terminal elimination half-life: 1.5-2.5 hours (adults); prolonged in hepatic impairment or neonates due to immature metabolism. |
| Protein binding | ~55% bound to alpha-1-acid glycoprotein and albumin. |
| Volume of Distribution | Vd: 1.0-1.5 L/kg (high tissue distribution, especially to highly perfused organs). |
| Bioavailability | Intravenous: 100%; Subcutaneous/Intramuscular: nearly 100% (complete absorption). |
| Onset of Action | Infiltration: 1-2 minutes; Epidural: 5-10 minutes; Nerve block: 5-15 minutes. |
| Duration of Action | Infiltration: 1-2 hours; Epidural: 1-3 hours; Nerve block: 1.5-3 hours (dose-dependent; prolonged with epinephrine). |
| Molecular Weight | 220.31 |
1-6 mL of 4% solution (40 mg/mL) by subcutaneous infiltration or nerve block, maximum 600 mg per dose; for epidural block, 10-15 mL of 2% or 3% solution
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required, but caution with severe renal impairment due to risk of accumulation of metabolites |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated or avoid use |
| Pediatric use | Weight-based: 0.5-2 mg/kg by infiltration or nerve block; maximum 3 mg/kg; for caudal epidural, 1-2 mg/kg |
| Geriatric use | Reduce dose by 20-30% due to age-related decreased clearance; monitor for prolonged effect and toxicity |
| 1st trimester | Prilocaine crosses the placenta. Studies in animals have shown teratogenic effects at high doses. Use only if clearly needed and benefit outweighs risk. |
| 2nd trimester | Consider fetal oxyhemoglobin levels; prilocaine may cause methemoglobinemia. Limited data in second trimester. Use with caution. |
| 3rd trimester | Prilocaine can cause fetal methemoglobinemia, especially with high doses. Use lowest effective dose. Avoid near term due to potential neonatal effects. |
Clinical note
Comprehensive clinical and safety monograph for CITANEST FORTE (CITANEST FORTE).
| Placental transfer | Prilocaine crosses the placenta freely. Fetal plasma concentrations may approach maternal levels. |
| Breastfeeding | Prilocaine is excreted into breast milk in small amounts. Use with caution in breastfeeding women; monitor infant for methemoglobinemia. The American Academy of Pediatrics considers it compatible with breastfeeding. |
■ FDA Black Box Warning
WARNING: METHEMOGLOBINEMIA - Prilocaine can cause methemoglobinemia, especially in patients with glucose-6-phosphate dehydrogenase deficiency, hemoglobin M disease, or those receiving other methemoglobin-inducing agents. Monitor for signs and symptoms of methemoglobinemia.
| Serious Effects |
Hypersensitivity to prilocaine or amide-type anestheticsSevere cardiovascular shockSevere hypotensionMyasthenia gravis (due to possibility of exacerbation)Congenital or idiopathic methemoglobinemia
| Precautions | Risk of methemoglobinemia, Avoid in patients with anemia, respiratory insufficiency, or cardiac compromise, IV administration should be avoided due to risk of systemic toxicity, Use with caution in patients with hepatic impairment, Monitor for neurological and cardiovascular toxicity signs |
| Food/Dietary | No specific food interactions are known. However, patients should avoid eating until sensation returns to prevent oral trauma. |
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| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | FDA Pregnancy Category B. Animal studies have not demonstrated fetal harm; no adequate human studies in first trimester. Use in second and third trimesters is associated with potential fetal bradycardia and acidosis due to uterine artery vasoconstriction and maternal hypotension. Risk of neonatal respiratory depression if administered shortly before delivery. |
| Fetal Monitoring | Continuous fetal heart rate monitoring during use; maternal blood pressure and oxygen saturation monitoring; assess for signs of methemoglobinemia via pulse oximetry (SpO2) and/or co-oximetry; observe neonate for respiratory depression and bradycardia if used near term. |
| Fertility Effects | No specific data on fertility impairment in humans. Animal studies show no adverse effects on reproductive parameters at clinically relevant doses. |
| Clinical Pearls | Citanest Forte (prilocaine with epinephrine) provides rapid onset and intermediate duration of local anesthesia. Due to prilocaine, there is a risk of methemoglobinemia, especially in infants, elderly, or patients with impaired oxygenation. Epinephrine prolongs anesthesia and reduces systemic absorption. Avoid use in patients with severe cardiovascular disease or peripheral vascular insufficiency. Do not exceed recommended doses to minimize toxicity. |
| Patient Advice | Inform your doctor if you have a history of heart disease, high blood pressure, thyroid problems, or blood disorders. · Avoid eating or drinking until numbness subsides to prevent accidental biting or burns. · If you experience bluish skin, lips, or nail beds, difficulty breathing, or extreme drowsiness, seek immediate medical attention. · Report any unusual bleeding or swelling at the injection site. · Do not drive or operate machinery until numbness resolves. |