Bupivacaine is a long-acting amide-type local anesthetic agent. The 5mg strength is typically used in specific, low-volume nerve blocks or as part of a dilute solution for infiltration or epidural analgesia. It provides profound sensory blockade with a variable degree of motor blockade, depending on concentration and site of administration. It is widely used in surgical anesthesia, obstetric analgesia, and postoperative pain management across India.
Adult: Dose varies EXTREMELY based on procedure, site, and patient status. 5mg is a component dose. Examples: Spinal anesthesia: 7.5-15mg (1.5-3mL of 0.5%). Epidural: Test dose of 3mL of 0.5% (15mg) with epinephrine. For infiltration, total dose should not exceed 175mg (with epinephrine) or 150mg (without).
Note: For injection only. Must be administered by trained professional. Aspirate before injection to avoid intravascular administration. Use incremental dosing. Solutions with or without preservatives are available; preservative-free solutions MUST be used for spinal/epidural/caudal blocks. Always check concentration (0.25%, 0.5%, 0.75%) and calculate total dose in mg before administration.
Bupivacaine reversibly binds to and inhibits voltage-gated sodium channels on the inner portion of neuronal cell membranes. This blockade prevents the transient increase in sodium ion permeability required for the generation and propagation of action potentials, leading to a reversible loss of sensation (sensory blockade) and, at higher concentrations, motor function (motor blockade) in the affected area.
Pregnancy: Category C (US FDA). Crosses placenta. Widely used for labor analgesia (epidural) and cesarean section anesthesia. Considered safe when used by experts for appropriate indications. Fetal bradycardia can occur. Avoid high doses and intravascular injection.
Driving: Patients must be warned that numbness and motor weakness may persist for several hours after regional anesthesia. They should NOT drive or operate machinery until full sensation and motor control have returned.
| Other Local Anesthetics | Additive toxic effects (CNS, cardiac). | Major |
| Antiarrhythmics (Class I e.g., Lidocaine, Mexiletine) | Additive cardiotoxicity and CNS toxicity. | Major |
| Beta-blockers (e.g., Propranolol) | Reduced hepatic clearance of bupivacaine, increased toxicity risk. | Moderate |
| CYP3A4 Inhibitors (e.g., Ketoconazole, Erythromycin, Verapamil) | Decreased metabolism, increased plasma levels and toxicity. | Moderate |
| CYP1A2 Inhibitors (e.g., Fluvoxamine, Ciprofloxacin) | Decreased metabolism, increased plasma levels. | Moderate |
| Vasoconstrictors (e.g., Epinephrine - when added to solution) | Prolongs duration of action, reduces systemic absorption. | Minor (Therapeutic) |
| MAO Inhibitors, Tricyclic Antidepressants | Potentiation of vasopressor effect if epinephrine is used. | Moderate |
| Succinylcholine | Prolonged neuromuscular blockade reported with large doses of local anesthetics. | Minor |
Same composition (Bupivacaine (5mg)), different brands: