Dose-dependent suppression of the neutrophil respiratory burst by lidocaine.

Abstract

Oxygen radical production is thought to be fundamental to the pathogenesis of post-ischaemic reperfusion injury which is routinely managed with lidocaine. Attention has, therefore, focused on the suppression of the neutrophil respiratory burst with a therapeutic endpoint. The widest application of lidocaine remains in local analgesia. A standard chemiluminescence technique was used to assess the human neutrophil leukocyte response to increasing doses of lidocaine in the presence or absence of particulate hydroxyapatite. No reduction of oxygen radical production was seen at the drug concentration of 1 mg/ml. A clear, concentration-dependent inhibition was seen at 2 mg/ml, 3 mg/ml, 4 mg/ml and 8 mg/ml concentrations. These drug concentrations may be reached at or near the site of injection in local anaesthetic use. Lidocaine showed profound anti-inflammatory action in this experimental system. Controlled studies in the clinical setting would identify the optimal analgesic and anti-inflammatory dosage, whilst preserving host defence without compromising tissue repair.