Levobupivacaine (rINN) is a local anaesthetic drug indicated for minor and major surgical anaesthesia and pain management. It is a long-acting amide-type local anaesthetic that blocks nerve impulses by inhibiting sodium ion influx into the nerve cells. Levobupivacaine is the S-enantiomer of racemic bupivacaine and therefore similar in pharmacological effects. The drug typically starts taking effect within 15 minutes and can last up to 16 hours depending on factors such as site of administration and dosage.
Levobupivacaine was designed, in the late 1970s, to be a safer and more effective alternative to bupivacaine, which had been associated with a higher risk of cardiotoxicity. Compared to bupivacaine, levobupivacaine is associated with less vasodilation and has a longer duration of action. It is approximately 13 per cent less potent (by molarity) than racemic bupivacaine and has a longer motor block onset time. Ropivacaine is, next to levobupivacaine, another less cardiotoxic alternative to bupivacaine.
Levobupivacaine hydrochloride is commonly marketed by AbbVie under the trade name Chirocaine. In Europe, Chirocaine is available – prescription only – in concentrations ranging from 0.625 mg/ml to 7.5 mg/mL.
Clinical use
Indications
Levobupivacaine, the S(-)-enantiomer of bupivacaine has been developed as an alternative to the racemic mixture, as it has been shown to have a lower cardiotoxicity than bupivacaine. Under European Union advice, it can be applied for minor and major surgical anaesthesia, as well as (post-operative) pain management. Particularly, it has been found suitable for multiple procedures, such as epidural block. It is effective for human patients who receive elective Caesarean section or lower body surgery, as it does not diverge dramatically in terms of sensory and/or motor block duration in comparison to bupivacaine. Deserving of consideration is the fact that its enhanced motor blocking can be a downside for patients receiving an epidural injection during childbirth, as a certain level of movement may still be required.
Other than childbirth, possible applications of levobupivacaine include upper and lower limb surgery, as well as eye surgery, where it blocks the extraocular muscle, highly efficient and convenient for patients undergoing vitreoretinal anterior segment or cataract surgery.
Levobupivacaine can be combined with other analgesics, including opioids, for postoperative pain management.
Contraindications
Using 0.75% (7.5 mg/ml) of levobupivacaine, similar to bupivacaine, is contraindicated in obstetric patients. Use in paracervical blocks in obstetrics is also contraindicated. Levobupivacaine is furthermore contraindicated in patients with known hypersensitivity to levobupivacaine or other amide-type local anaesthetics, in patients with severe hypotension (e.g. cardiac or hypovolemic shock) and for use in intravenous regional anaesthesia (Bier’s block).
Adverse effects
Possible adverse effects in the central nervous system caused by levobupivacaine usage are light-headedness, tinnitus, tongue numbness and convulsions, which may be due to the blockade of sodium, potassium and calcium channels in tissues that were not intended as targets. Cardiotoxicity may be a result of indirect effects of the drug, such as the blockade of myocardial sympathetic nerves, thus leading to contractile delay, or by direct effects, such as the blockade of potassium channels.
Effects of this nature lead to lowered contractile function and arrhythmogenic effects, which can potentially cause cardiovascular collapse and death. It is to note that the drug also has vasoconstrictive activity, thereby increasing the duration of sensory blockage with a relatively low risk of central nervous system toxicity on one hand, and on the other, it can have the same effect on uteroplacental blood flow, which can harm the foetus. Ultimately, levobupivacaine has been shown to have a lower risk of cardiovascular and central nervous system toxicity compared to bupivacaine in animal studies, not at the expense of potency and efficacy, and should be therefore considered as an alternative.