Prolonged analgesia after cuff release following i.v. regional analgesia with prilocaine

In a prospective randomized study, 60 outpatients received 0.8%, 1.5% or 2% prilocaine (4 mg/kg body weight) as i.v. regional anaesthesia for operations in the carpal region. The latent period, quality and duration of analgesia after release of the tourniquet were analysed. The latent period was shortest with 2% prilocaine. The duration of analgesia after tourniquet release increased from 5.7 min with 0.8% to 15.6 min with 2% prilocaine. The plasma concentrations after 1.5% prilocaine were significantly less than with 0.8% prilocaine.