Bupivacaine is an amide local anaesthetic.
It is a clear, colourless solution prepared as a 0.25 and 0.5% (with or without epinephrine 1:200,000). For subarachnoid block, a 0.5% (heavy) solution containing 80 mg/ml glucose (specific gravity 1.026) is available.
The toxic dose of bupivacaine is 2 mg/kg (with or without epinephrine). It is one of the more cardiotoxic local anaesthetics. Bupivacaine is therefore contraindicated for i.v. regional anaesthesia (IVRA) because of potential risk of tourniquet failure and systemic absorption of the drug.
Bupivacaine may be administered by infiltration, intrathecally and epidurally. It is commonly used for epidural infusions (with or without an opioid) for labour and postoperatively.
Because of the pKa of 8.1, the onset of action is intermediate or slow. Bupivacaine is the most highly protein-bound (95%) amide local anaesthetic, which is the reason for its long duration of action. It is metabolised in the liver by N-dealkylation to pipecolylxylidine and pipecolic acid.