SENSORCAINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SENSORCAINE (SENSORCAINE).
SENSORCAINE (bupivacaine) is an amide-type local anesthetic that blocks sodium ion channels in nerve cell membranes, thereby inhibiting depolarization and propagation of action potentials, resulting in reversible local anesthesia.
| Metabolism | Primarily metabolized by the liver via conjugation with glucuronic acid; also hydrolyzed by plasma pseudocholinesterase to form pipecolylxylidine (PPX), the major metabolite. |
| Excretion | SENSORCAINE (bupivacaine) is primarily metabolized in the liver via conjugation with glucuronic acid and undergoes hepatic dealkylation. Approximately 6% of the drug is excreted unchanged in the urine. The majority of the dose (about 95%) is excreted as metabolites in the urine (<10% unchanged) and the remainder in feces via biliary elimination. |
| Half-life | The terminal elimination half-life of bupivacaine is approximately 2.7 hours in adults (range 1.5–5.5 hours). In neonates, the half-life is significantly prolonged (~8–12 hours) due to immature hepatic function, leading to an increased risk of toxicity. |
| Protein binding | Bupivacaine is highly protein-bound (~95%) primarily to alpha-1-acid glycoprotein (AAG) and to a lesser extent albumin. Binding is concentration-dependent and saturable; increased free fraction in conditions with low AAG (e.g., pregnancy, neonates, critical illness). |
| Volume of Distribution | Volume of distribution (Vd) at steady state is approximately 0.6–1.0 L/kg in adults (range 50–100 L). The large Vd reflects extensive tissue distribution, with rapid uptake into well-perfused organs (brain, heart, liver, kidneys). |
| Bioavailability | Bioavailability after epidural administration is approximately 98% due to extensive vascular absorption from the epidural space. For intravenous administration, bioavailability is 100%. Oral bioavailability is low (~30–40%) due to extensive first-pass metabolism. |
| Onset of Action | Onset of action varies by route: Epidural (lumbar): 15–25 minutes for surgical anesthesia; Caudal: 6–10 minutes; Peripheral nerve block: 10–15 minutes; Local infiltration: 1–5 minutes; Intrathecal: rapid (<5 minutes). |
| Duration of Action | Duration is dose-dependent: Epidural: 2–4 hours for surgical anesthesia (up to 6 hours with epinephrine); Peripheral nerve block: 3–8 hours; Local infiltration: 1–3 hours. Prolonged duration due to high protein binding and slow release from tissue binding sites. |
Epidural or caudal block: 15-30 mL of 0.5% to 1% solution (75-150 mg) every 2-4 hours as needed. Maximum single dose: 225 mg.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for mild to moderate impairment (GFR ≥30 mL/min). Severe impairment (GFR <30 mL/min): reduce dose by 50% and monitor for CNS toxicity. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: contraindicated. |
| Pediatric use | Neonates and infants: 0.5-1 mg/kg by infiltration or nerve block, maximum 4 mg/kg/day. Children: 1-2 mg/kg per dose, maximum 5 mg/kg/day. |
| Geriatric use | Reduce initial dose by 30-50% due to reduced clearance and increased sensitivity; titrate carefully. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SENSORCAINE (SENSORCAINE).
| Breastfeeding | Bupivacaine is excreted in human breast milk in low concentrations. The milk-to-plasma ratio is approximately 0.3. Although it is considered compatible with breastfeeding, caution is advised due to the potential for cumulative local anesthetic effects in the infant, especially with repeated doses. Monitor the infant for drowsiness and feeding difficulties. |
| Teratogenic Risk | Sensorcaine (bupivacaine) is classified as FDA Pregnancy Category C. In the first trimester, there is a potential risk of developmental abnormalities based on animal studies showing increased fetal resorptions and delayed ossification at high doses. During the second and third trimesters, no significant teratogenic effects have been reported in humans, but the drug may cause fetal bradycardia and metabolic acidosis due to increased placental transfer near term. Use only if clearly needed. |
■ FDA Black Box Warning
SENSORCAINE with epinephrine is not recommended for obstetrical use (paracervical block) as it can cause fetal bradycardia and death. All local anesthetics, including bupivacaine, may cause methemoglobinemia.
| Serious Effects |
["Hypersensitivity to bupivacaine or other amide-type anesthetics","Severe hypotension (e.g., hypovolemic shock)","Sinoatrial block, advanced AV block, or uncontrolled cardiac arrhythmias","Obstetrical paracervical block (with epinephrine)","Intra-articular use in knee arthroscopy (with epinephrine)","Midline cesarean block and lower limb surgery when not indicated"]
| Precautions | ["Risk of cardiac arrest and death with high doses or rapid injection, especially in elderly or debilitated patients","Chondrolysis risk with intra-articular infusions","Neurologic injury with spinal/epidural use","Methemoglobinemia risk, especially in neonates","Hypotension and bradycardia with epidural use","Systemic toxicity from accidental intravascular injection"] |
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| Fetal Monitoring | Monitor maternal heart rate, blood pressure, and respiratory status during administration. Fetal heart rate monitoring is recommended during labor and delivery due to possible fetal bradycardia. Assess for signs of local anesthetic systemic toxicity (LAST) including dizziness, perioral numbness, and convulsions. |
| Fertility Effects | No adverse effects on fertility have been reported with bupivacaine. Animal studies show no impairment of fertility at clinically relevant doses. However, high doses may cause transient changes in sperm motility in animal models; clinical significance in humans is unknown. |