Liposomal Bupivacaine
Exparel
Extended-release liposomal amide local anesthetic
Bupivacaine encapsulated in multivesicular liposomes → slow release over ~72 h for prolonged postoperative analgesia.
Indications
- •Surgical-site infiltration
- •Selected nerve blocks (e.g., interscalene, TAP) for prolonged postop analgesia (ERAS)
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Infiltration | Up to 266 mg (20 mL) — do not exceed labeled max | — |
Pharmacokinetics
Release over ~72 h; peak plasma bimodal. Do NOT admix with other LAs beyond labeled windows (disrupts liposomes → bolus release).
Side effects
- !LAST (if liposomes disrupted → bolus release)
- !Cost
- !Efficacy vs plain bupivacaine debated
Contraindications
- ×OB paracervical block
- ×Admixture with non-bupivacaine LAs / topical use
Clinical pearls
- ★Do NOT mix with lidocaine or give other LAs at the site within ~20 min — disrupting liposomes dumps bupivacaine (LAST).
- ★Marketed for ~72 h analgesia; real-world benefit over plain bupivacaine is modest/contested.
Other drugs in Local Anesthetics
- Lidocaine
Blocks voltage-gated Na⁺ channels in nerves (LA) and cardiac myocytes (antiarrhythmic).
- Bupivacaine
Voltage-gated Na⁺ channel blocker. Higher protein binding and lipid solubility than lidocaine → longer duration but greater cardiotoxicity.
- Ropivacaine
S-enantiomer of propivacaine. Less lipid-soluble than bupivacaine → less cardiotoxicity but slightly less potency.
- Tetracaine
Blocks voltage-gated Na⁺ channels. Long-acting ester, metabolized by plasma cholinesterase. High potency + toxicity.
- Chloroprocaine
Na⁺-channel blocker. Extremely rapid plasma-cholinesterase metabolism (half-life seconds) → lowest systemic toxicity of the LAs, ideal for OB epidural top-up.
- Procaine
Na⁺-channel blocker; prototype ester LA. Plasma-cholinesterase metabolized to PABA.
- Prilocaine
Na⁺-channel blocker. Metabolized to o-toluidine → oxidizes hemoglobin → methemoglobinemia at high doses.
Suggested reading
- •Stoelting & Hines, Pharmacology & Physiology in Anesthetic Practice, 6e
- •FDA package insert
- •ASRA LAST checklist, 2020
