CARBOCAINE W/ NEO-COBEFRIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CARBOCAINE W/ NEO-COBEFRIN (CARBOCAINE W/ NEO-COBEFRIN).
Mepivacaine is an amide-type local anesthetic that blocks sodium ion channels in nerve cell membranes, inhibiting nerve impulse conduction. Neo-cobefrin (levonordefrin) is a vasoconstrictor that acts on alpha-adrenergic receptors to constrict blood vessels, prolonging mepivacaine's action.
| Metabolism | Primarily hepatic via CYP450 enzymes (mainly CYP3A4 and CYP1A2) for mepivacaine; levonordefrin is metabolized by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). |
| Excretion | Renal excretion of unchanged drug and metabolites; ~1-2% unchanged in urine; hepatic metabolism to inactive metabolites; biliary/fecal elimination minimal |
| Half-life | Terminal elimination half-life ~2-3 hours; prolonged in hepatic impairment; clinical context: short duration of action |
| Protein binding | ~85-95% bound to alpha-1-acid glycoprotein and albumin |
| Volume of Distribution | Vd ~0.9-1.1 L/kg; clinical meaning: moderate distribution, higher in neonates |
| Bioavailability | Epidural: near 100%; Subcutaneous/infiltration: near 100% due to no first-pass; Oral: negligible due to high first-pass metabolism |
| Onset of Action | Infiltration: 1-2 minutes; Epidural: 5-15 minutes; Peripheral nerve block: 5-20 minutes |
| Duration of Action | Infiltration: 0.5-1 hour; Epidural: 1-2 hours; Peripheral nerve block: 1-3 hours; shorter than bupivacaine; duration extended with epinephrine |
| Molecular Weight | 282.4 |
1-2% mepivacaine with 1:200,000 levonordefrin. Maximum dose: mepivacaine 400 mg (5 mg/kg); for dental infiltration: 0.5-1.8 mL, nerve block: 0.9-3.6 mL, epidural: 15-30 mL of 1% or 2% solution.
| Dosage form | INJECTABLE |
| Renal impairment | GFR ≥60 mL/min: no adjustment; GFR 30-59: caution, reduce dose by 25-50%; GFR 15-29: reduce dose by 50% and monitor for toxicity; GFR <15: avoid or use with extreme caution. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated. |
| Pediatric use | Maximum dose: 5 mg/kg or 400 mg total; use 1% solution. For infiltration: 0.5-1 mg/kg; nerve block: 1-2 mg/kg; epidural: 1-2 mg/kg. |
| Geriatric use | Reduce dose by 20-50% due to decreased clearance; maximum dose 300 mg; use 1% solution; monitor for cardiovascular and CNS toxicity. |
| 1st trimester | Limited human data; animal studies not available. Fetal risk cannot be ruled out. Use only if clearly needed. |
| 2nd trimester | Generally considered safe in standard doses for regional anesthesia. Monitor for maternal hypotension and fetal bradycardia. |
| 3rd trimester | Safe for use in labor and delivery; avoid accidental intravascular injection. May cause fetal bradycardia due to uterine artery vasoconstriction. |
Clinical note
Comprehensive clinical and safety monograph for CARBOCAINE W/ NEO-COBEFRIN (CARBOCAINE W/ NEO-COBEFRIN).
| Placental transfer | Crosses placenta via passive diffusion. Degree affected by protein binding and ionization; mepivacaine transfer is moderate (fetal/maternal ratio ~0.6-0.8) due to 70% protein binding. |
| Breastfeeding | Mepivacaine and levonordefrin are excreted in breast milk in very small amounts; unlikely to cause adverse effects in the nursing infant. Use with caution, especially with repeated doses. |
■ FDA Black Box Warning
Not for intravenous administration; inadvertent intravascular injection may cause cardiac arrest or death. Resuscitative equipment and trained personnel must be available immediately.
| Serious Effects |
Known hypersensitivity to amide-type anesthetics or sulfitesSevere hypotension or cardiogenic shockSevere bradyarrhythmias or heart block (unless paced)Uncontrolled hyperthyroidism (due to levonordefrin)Severe hypertension (due to levonordefrin)Concurrent use of MAO inhibitors or tricyclic antidepressants (risk of hypertensive crisis due to levonordefrin)Paracervical block in obstetrics (associated with fetal bradycardia)
| Precautions | Avoid systemic toxicity; use smallest effective dose, Caution in patients with hepatic impairment, cardiovascular disease, or hypertension, Risk of methemoglobinemia in susceptible patients, May cause arrhythmias in patients on tricyclic antidepressants or MAO inhibitors |
| Food/Dietary | No specific food interactions. Avoid hot foods or beverages until numbness resolves to prevent burns. |
Loading safety data…
| Lactation Rating | L2 |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: No adequate studies; animal studies have shown teratogenic effects at doses 7 times the maximum recommended human dose. Second and third trimesters: Local anesthetics may cause fetal bradycardia and central nervous system depression; risk of methemoglobinemia with prilocaine component. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and oxygen saturation. Fetal heart rate monitoring is recommended during labor and delivery. Observe for signs of systemic toxicity (e.g., seizures, cardiac arrhythmias) and methemoglobinemia (particularly with prilocaine). Assess for fetal distress if used in obstetrics. |
| Fertility Effects | No human studies on fertility. Animal studies have not shown impairment of fertility at clinically relevant doses. Theoretical concern for sperm motility impairment with local anesthetics, but clinical significance is unknown. |
| Clinical Pearls | Carbocaine (mepivacaine) with Neo-Cobefrin (levonordefrin) is a local anesthetic with vasoconstrictor. Levonordefrin is a sympathomimetic amine; avoid in patients on MAOIs or with severe hypertension. Maximum dose: mepivacaine 400 mg (with epinephrine) or 300 mg (without); for levonordefrin, max 0.5 mg per appointment. Use with caution in patients with cardiovascular disease, hyperthyroidism, or sulfite allergy (if formulation contains sulfites). Levonordefrin is less potent than epinephrine; may require higher concentration for equivalent hemostasis. |
| Patient Advice | This medication is used to numb a specific area before a dental or minor surgical procedure. · Do not eat or chew on the numb area until sensation returns to avoid accidental injury. · Contact your healthcare provider if you experience chest pain, rapid heartbeat, severe headache, or difficulty breathing after the injection. · If you have a history of high blood pressure, heart disease, thyroid problems, or are taking MAO inhibitors, inform your dentist or doctor before receiving this anesthetic. · Numbness and tingling may last for several hours; avoid hot foods or beverages until feeling returns. · Do not exceed the recommended dose; additional injections may be necessary but should be spaced appropriately. |