Bupivacaine Injections

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Bupivacaine Injections Bupivacaine is a long‐acting amide local anesthetic used for surgical and pain blocks (infiltration, nerve blocks, epidural, etc.). It is chemically related to lidocaine/mepivacaine but is more lipid‐soluble and protein-bound, giving it a slower onset and much longer duration of anesthesia. Brand names include Marcaine and Sensorcaine (bupivacaine HCl) for injections, and Exparel for the liposomal (extended-release) formulation. Bupivacaine works by blocking voltage-gated sodium channels in nerve membranes, preventing depolarization and thus nerve impulse conduction. In clinical order, sensation lost is pain → temperature → touch → motor function . Available Strengths and Formulations Bupivacaine injections come in several concentrations (all as mg per mL ): 0.25% (2.5 mg/mL): Provides mild anesthesia with minimal motor block. Used for minor infiltration or prolonged procedures not requiring deep muscle relaxation. (Available as Marcaine/Sensorcaine 0.25% in 10 mL or 30 mL single-dose vials and 50 mL multi-dose vials . 0.5% (5 mg/mL): The most common standard strength. Used for many peripheral nerve blocks, epidural labor analgesia, dental procedures, etc. (Available in 10 mL, 30 mL single-dose and 50 mL multi-dose vials . 0.75% (7.5 mg/mL): A higher concentration for deeper anesthesia (e.g. surgical blocks requiring complete motor block, retrobulbar eye blocks, some epidurals). Not recommended for obstetrical epidurals due to reports of cardiotoxicity. (Sold in 10 mL and 30 mL vials; e.g. Marcaine 0.75%.) With epinephrine (1:200,000): Bupivacaine 0.25% and 0.5% are also available combined with epinephrine to constrict blood vessels, slow absorption, and prolong duration (e.g. Marcaine with epi 0.5% in 1:200,000). Epinephrine-containing solutions carry additional warnings (see below). Other formulations: A 0.75% (7.5 mg/mL) heavy solution with 8.25% dextrose is sold as LIDOCAINE Marcaine™ Spinal for intrathecal (spinal) anesthesia (hyperbaric