Comparative Pharmacology
Head-to-head clinical analysis: EXPAREL versus MARCAINE HYDROCHLORIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EXPAREL versus MARCAINE HYDROCHLORIDE.
EXPAREL vs MARCAINE HYDROCHLORIDE
Head-to-head clinical comparison of therapeutic indices and safety profiles.
Liposomal bupivacaine is a local anesthetic that blocks sodium channels in nerve cell membranes, inhibiting nerve impulse conduction and providing prolonged analgesia.
Bupivacaine is an amide-type local anesthetic that blocks voltage-gated sodium channels in nerve cell membranes, reversibly inhibiting nerve impulse propagation, particularly in sensory fibers.
Single-dose infiltration for postsurgical analgesia in adultsInterscalene brachial plexus nerve block for postsurgical analgesia in adults
Local infiltration anesthesiaPeripheral nerve blockCentral neuraxial block (epidural, spinal)Dental proceduresPostoperative pain managementObstetrical anesthesia (epidural)
Local infiltration: up to 266 mg (20 mL) as a single dose; interscalene brachial plexus block: up to 133 mg (10 mL); femoral nerve block: up to 133 mg (10 mL). Maximum dose 266 mg. Administer via slow injection with frequent aspiration.
Adults: 0.5% solution infiltrated up to 175 mg (35 mL) for minor procedures; for major procedures, up to 225 mg (45 mL) with epinephrine. Repeat doses at 3-hour intervals. Maximum dose 400 mg with epinephrine.
None Documented
None Documented
Terminal elimination half-life is 12-48 hours (mean ~24 hours), reflecting prolonged release from the multivesicular liposome depot.
Terminal elimination half-life is approximately 2.5 to 3.5 hours in adults; may be prolonged in neonates (8-12 hours) or patients with hepatic impairment.
Hepatic metabolism primarily via conjugation with glucuronic acid; minor metabolism by CYP450 enzymes (CYP3A4, CYP1A2, CYP2D6).
Primarily hepatic via CYP1A2 and CYP3A4; major metabolite is pipecolylxylidine (PPX).
Renal (approximately 96% as metabolites, <10% unchanged). Biliary/fecal excretion is negligible.
Primarily hepatic metabolism; less than 5% excreted unchanged in urine. Metabolites are excreted renally, with a small amount in feces via biliary elimination.
Approximately 96% bound to alpha-1-acid glycoprotein (AAG) and albumin, with binding dependent on drug concentration and AAG levels.
Approximately 95% bound primarily to alpha-1-acid glycoprotein and albumin.
After IV administration of free bupivacaine: ~0.6-0.8 L/kg. For Exparel, Vd is not directly applicable due to local administration; systemic Vd reflects released bupivacaine.
1.3 L/kg; indicates extensive tissue distribution, characteristic of lipophilic amide local anesthetics.
Not applicable for IV route; after local infiltration, systemic bioavailability is essentially 100% due to complete absorption from the depot over time.
Not applicable for injection; negligible oral bioavailability due to extensive first-pass metabolism. For infiltration or nerve block, bioavailability is 100% at the site of administration.
No dosage adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (eGFR <30 mL/min/1.73 m²); use with caution.
No specific dose adjustment recommended for GFR > 30 mL/min. For GFR < 30 mL/min, reduce dose by 25-50% and monitor for toxicity.
No dosage adjustment required for mild hepatic impairment (Child-Pugh A). Not studied in moderate to severe impairment (Child-Pugh B or C); use with caution due to potential for increased systemic exposure.
Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose by 40%. Child-Pugh C: Contraindicated or use with extreme caution and 50% dose reduction.
Not recommended for use in pediatric patients <18 years of age due to lack of safety and efficacy data.
Weight-based: 0.5% solution, maximum 2 mg/kg for infiltration; for regional blocks, 1.5 mg/kg. With epinephrine, up to 3 mg/kg. Use lowest effective dose.
No specific dosage adjustment required. Monitor for prolonged duration of sensory and motor block; consider reduced doses based on clinical status (e.g., frailty, comorbidities).
Elderly: Reduce dose by 20-30% due to age-related decreases in clearance; use lower concentrations (0.25%) and minimal volumes. Monitor for CNS and cardiac effects.
None.
Risk of cardiac arrest and seizures following unintentional intravascular injection; use with extreme caution when administering large doses. Avoid rapid injection. Resuscitative equipment and personnel trained in advanced cardiac life support must be immediately available.
["Avoid intravascular injection; may result in cardiac arrest or severe systemic toxicity.","Not recommended for use in children under 18 years.","Use with caution in patients with hepatic impairment, severe renal impairment, or cardiovascular disease.","Risk of chondrolysis when used for intra-articular infusions.","Do not use in epidural, intrathecal, or intravenous routes."]
Risk of systemic toxicity (CNS and cardiovascular), particularly with high doses or accidental intravascular injection. Use with caution in patients with hepatic impairment, cardiac disease, or myasthenia gravis. Monitor for signs of methemoglobinemia (rare). Avoid use in patients with severe hypotension or shock.
["Hypersensitivity to bupivacaine or any amide-type local anesthetics","Obstetrical paracervical block anesthesia"]
Known hypersensitivity to bupivacaine or other amide-type anesthetics, severe pre-existing hypotension, bacteremia, thrombocytopenia, coagulopathy (for neuraxial use), obstetrical paracervical block anesthesia (due to fetal bradycardia).
Data Pending Review
Data Pending Review
No known food interactions. Avoid alcohol consumption as it may increase the risk of central nervous system depression.
No known food interactions.
EXPAREL (liposomal bupivacaine) has not been studied in pregnant women. Animal reproduction studies have not been conducted with EXPAREL. Bupivacaine HCl, the active moiety, crosses the placenta. In pregnant women, bupivacaine can cause fetal bradycardia and neonatal depression when used for labor analgesia. Use during first trimester: Limited data; risk cannot be excluded. Use during second trimester: Consider risk-benefit. Use during third trimester: Avoid high doses near term due to potential fetal and neonatal adverse effects.
Bupivacaine hydrochloride is classified as FDA Pregnancy Category C. In the first trimester, there is a potential risk of teratogenicity based on animal studies showing adverse effects at high doses, but no well-controlled human studies exist. During the second and third trimesters, use may cause fetal bradycardia, acidosis, and central nervous system depression due to placental transfer. Risk of fetal hypoxia and bradycardia increases with higher doses or inadvertent intravascular injection. Paracervical block in early pregnancy is associated with fetal bradycardia.
Bupivacaine is excreted in human milk in small amounts. The milk-to-plasma (M/P) ratio for bupivacaine is approximately 0.3 to 0.5. After epidural administration, the relative infant dose is estimated to be <4% of the maternal weight-adjusted dose. EXPAREL has not been studied in lactating women. Clinical implications: Caution is advised; monitor the infant for signs of local anesthetic toxicity (e.g., irritability, feeding difficulties).
Bupivacaine is excreted into breast milk in low concentrations (estimated M/P ratio approximately 0.2–0.4). The relative infant dose is estimated at <2% of maternal weight-adjusted dose, considered compatible with breastfeeding. However, caution is advised if the infant has reduced metabolic capacity or if repeated high maternal doses are used. Monitor infant for signs of local anesthetic toxicity (e.g., lethargy, poor feeding).
Pharmacokinetic changes in pregnancy (e.g., increased volume of distribution, decreased plasma protein binding) may alter bupivacaine disposition. However, specific dose adjustment guidelines for EXPAREL in pregnancy are not established. The dose should be individualized based on the surgical site, patient weight, and clinical condition. Avoid exceeding the maximum recommended dose (266 mg for single-dose administration). Use with caution in severe preeclampsia or hepatic impairment due to altered clearance.
Pregnancy may increase clearance and volume of distribution, potentially requiring higher doses for epidural anesthesia. However, the risk of toxicity and fetal exposure limits dose increases; use lowest effective dose. Epidural doses may need reduction due to increased sensitivity to local anesthetics and decreased protein binding (increased free fraction). Fractionated dosing and test doses are recommended. No specific dose adjustment guidelines; clinical judgment based on maternal response and fetal status.
Category C
Category C
Exparel (liposomal bupivacaine) is a long-acting local anesthetic formulation. It should not be used in place of traditional local anesthetics for immediate postoperative pain control; a short-acting agent may be co-administered. Avoid concurrent use with other local anesthetics as it may alter liposomal release. Do not use with non-bupivacaine local anesthetics. Exparel is contraindicated in patients with hypersensitivity to bupivacaine or amide anesthetics. Do not administer intravascularly; monitor for CNS and cardiac toxicity. Use with caution in hepatic impairment. Maximum dose is 266 mg (20 mL of 1.3% solution) in adults.
Bupivacaine is highly protein-bound and has a slow dissociation from sodium channels, resulting in prolonged duration of action. Use with caution in hepatic impairment due to extensive liver metabolism. Avoid intravenous regional anesthesia (Bier block) as it can cause severe cardiac toxicity. Maximum single dose for infiltration is 175 mg (without epinephrine) or 225 mg (with epinephrine).
Exparel is a long-acting numbing medicine that provides pain relief for up to 72 hours after surgery.It is injected into the surgical site by your doctor before or during surgery.You may still feel some sensation, but pain should be significantly reduced.Do not apply heat or cold packs directly over the injection area for 24 hours.Avoid strenuous activity or heavy lifting until your doctor advises it is safe.Seek medical help if you experience symptoms like severe headache, confusion, ringing in ears, vision changes, or metallic taste.
Report any numbness or weakness that persists longer than expected.Seek immediate medical attention if you experience ringing in ears, metallic taste, or dizziness.Avoid driving or operating machinery until full sensation and motor function return.Inform your doctor if you have liver disease or are taking antiarrhythmic drugs.