Lidocaine
Commonly used for local anaesthetic infiltration, which will not be considered further here.
Rarely, it can be used as a short duration intravenous infusion by PAIN TEAM, CONSULTANT ANAESTHETIST or ICU ONLY
Mechanism of action: Local anaesthetics block nerve conduction by reversibly binding with the alpha subunit of voltage-gated sodium channels in the nerve cell membrane. The site of action is intracellular, requiring local anaesthetics to diffuse across the lipophilic cell membrane. Intravenous lidocaine appears to have anti-nociceptive, anti-hyperalgesic and anti-inflammatory actions.
Presentation: solution for injection of various concentrations, medicated plaster (restricted use to pain team recommendation only in OUH)
Maximum dose: initial dose of 1.5mg/kg (ideal body weight) given over 10 minutes. Then infusion of no more than 1.5mg/kg/h for no longer than 24 hours, in a high dependency setting and observe carefully for signs of local anaesthetic toxicity [link to LA toxicity].
Caution: Intravenous lidocaine can be fatal if used inappropriately and incorrectly. Do not start iv lidocaine within 4 hours after any nerve block, and do not perform any nerve block until 4 hours after discontinuing an iv lidocaine infusion.
Protein binding: 70%
pKa: 7.7
Metabolism: Primarily hepatic, with 95% metabolised by cytochrome P450 enzymes
Elimination: metabolites and 10% of unchanged drug excreted by the kidneys.
Half-life: 90 minutes, prolonged two-fold in liver dysfunction
Further prescribing information (side effects, contraindications, interactions):