Pharmacokinetics of 0.5% levobupivacaine following ilioinguinal-iliohypogastric nerve blockade in children

Background: Bupivacaine (2 mg kg(-1)) has been recommended for blockade of the ilioinguinal and iliohypogastric nerves in paediatric patients undergoing inguinal surgery. We determined the plasma concentrations of levobupivacaine following ilioinguinal-iliohypogastric block. Methods: Twenty children scheduled for elective surgery for inguinal surgery received 2 mg kg(-1) of 0.5% levobupivacaine. Surgical anaesthesia was maintained with mask inhalation of oxygen, nitrous oxide and sevoflurane. Venous blood samples were drawn at regular intervals up to 2 h and plasma was separated. Total venous plasma concentrations were determined by gas chromatography. Bupivacaine concentrations from a study with a similar protocol were used as historical controls for comparison. Results: The groups were similar with respect to age, weight and dosage of local anaesthetic. The initial distribution half-time (Talpha), the peak plasma concentration (Cmax) achieved, the time to the peak plasma concentration were similar (Tmax), and the mean areas under the concentration time curve (AUC) were similar between the two local anaesthetics. Conclusion: Levobupivacaine and bupivacaine are equally absorbed to similar maximum concentrations.