Levobupivacaine

Absorption

The plasma concentration of levobupivacaine following therapeutic administration depends on dose and also on route of administration, because absorption from the site of administration is affected by the vascularity of the tissue. Peak levels in blood were reached approximately 30 minutes after epidural administration, and doses up to 150 mg resulted in mean Cmax levels of up to 1.2 μg/mL.

Toxicity

LD50: 5.1mg/kg in rabbit, intravenous; 18mg/kg in rabbit, oral; 207mg/kg in rabbit, parenteral; 63mg/kg in rat, subcutaneous (Archives Internationales de Pharmacodynamie et de Therapie. Vol. 200, Pg. 359, 1972.) Levobupivacaine appears to cause less myocardial depression than both bupivacaine and ropivacaine, despite being in higher concentrations.

The Uses of Levobupivacaine

Local anaesthetic used for epidural and intrathecal anaesthesia.

Background

Levobupivacaine is an amino-amide local anaesthetic drug belonging to the family of n-alkylsubstituted pipecoloxylidide. It is the S-enantiomer of bupivacaine. Levobupivacaine hydrochloride is commonly marketed by AstraZeneca under the trade name Chirocaine. In particular, the specific levobupivacaine enantiomer is a worthwhile pursuit because it demonstrates less vasodilation and possesses a greater length of action in comparison to bupivacaine. It is approximately 13 per cent less potent (by molarity) than racemic bupivacaine.Levobupivacaine is indicated for local anaesthesia including infiltration, nerve block, ophthalmic, epidural and intrathecal anaesthesia in adults; and infiltration analgesia in children. When administered appropriately, the occurrence of adverse effects is not anticipated much if at all. In general, the majority of potential adverse effects are predominantly associated with inappropriate administration methods that may cause systemic exposure and/or toxicity associated with overexposure to an anesthetic. Regardless, allergic reactions may also occur - although only rarely.

Indications

For the production of local or regional anesthesia for surgery and obstetrics, and for post-operative pain management

Pharmacokinetics

Levobupivacaine, a local anesthetic agent, is indicated for the production of local or regional anesthesia or analgesia for surgery, for oral surgery procedures, for diagnostic and therapeutic procedures, and for obstetrical procedures.

Metabolism

Levobupivacaine is extensively metabolized with no unchanged levobupivacaine detected in urine or feces. In vitro studies using [14 C] levobupivacaine showed that CYP3A4 isoform and CYP1A2 isoform mediate the metabolism of levobupivacaine to desbutyl levobupivacaine and 3-hydroxy levobupivacaine, respectively. In vivo, the 3-hydroxy levobupivacaine appears to undergo further transformation to glucuronide and sulfate conjugates. Metabolic inversion of levobupivacaine to R(+)-bupivacaine was not evident both in vitro and in vivo.