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.