Observation of potential lidocaine toxicity during local anesthesia administration for punch skin biopsy in dogs.

________________________________________________________________________________________ LEMO, N., D. VNUK, F. BANOVIC: Observation of potential lidocaine toxicity during local anesthesia administration for punch skin biopsy in dogs. Vet. arhiv 85, 523-532, 2015. ABSTRACT Punch biopsies are a widely used diagnostic method in veterinary dermatology. During a biopsy, it is necessary to use local anesthesia and/or sedation to prevent pain. Lidocaine is a local analgesic drug that is often used. Adding adrenaline to lidocaine solutions for local anesthesia potentiates and prolongs its analgesic action. Intravenous lidocaine administration has been reported to cause signifi cant side effects, seizures being considered the most common sign of intoxication, while bradyarrhythmia and conduction disturbances are less prevalent. The aim of this study is to investigate the potential lidocaine toxicity effect of two frequently used local anesthetic solutions, lidocaine and lidocaine/adrenaline combination. Nine healthy dogs were randomly assigned into two groups. One group (n = 4) received subcutaneous injections of lidocaine (total of six 1 mL injections of 2 % lidocaine solution), while the dogs in the second group (n = 5) received a lidocaine/adrenaline combination (total of six 1 mL injections of 2 % lidocaine solution plus 0.0125 mg adrenaline tartarate). None of the known lidocaine side effects were observed. The blood concentration of lidocaine was far below the reported convulsive threshold in dogs. Subcutaneous administration of two different lidocaine local anesthetic formulations was shown to be well tolerated and safe. This research suggests that lidocaine and lidocaine/ adrenaline formulation can be safely used as a local anesthetic for skin punch biopsies in dogs with body mass greater than 5 kg.