Drugs that reversibly block nerve conduction to numb a region.
Key points
• Work by blocking voltage-gated sodium channels.
• Two classes: esters (procaine) and amides (lidocaine, bupivacaine).
• Toxicity may cause CNS symptoms such as perioral tingling and seizures and can progress to cardiovascular toxicity; adrenaline is used with certain local anaesthetics to reduce systemic absorption and may prolong their effect.
Memory trick
Amide local anaesthetics have an 'i' before -caine (lIdocaine, bupIvacaine).