Local anaesthesia in the operating theatre

Area of Science:

• Pharmacology
• Anesthesiology

Background:

• Cocaine was the first local anesthetic, introduced in 1884.
• Regional anesthesia, or pain relief by nerve blockade, was first described in 1901.

Purpose of the Study:

• To review the historical development and chemical properties of local anesthetic drugs.
• To discuss the pharmacokinetic differences between ester- and amide-linked local anesthetics.
• To highlight factors influencing drug degradation and potential adverse reactions.

Main Methods:

• Historical review of local anesthetic development.
• Chemical structure analysis of local anesthetic molecules.
• Pharmacokinetic and pharmacodynamic comparison of ester- and amide-linked agents.

Main Results:

• Local anesthetics are water-soluble salts of lipid-soluble alkaloids, with aromatic, intermediate, and amide portions.
• Ester-linked anesthetics are rapidly hydrolyzed in plasma (1-8 min half-life); amide-linked anesthetics are metabolized in the liver (1.5-3+ hr half-life).
• Vasoconstrictors like adrenaline prolong action; liver conditions affect amide-linked drug metabolism, and ester-linked drugs are associated with more anaphylaxis.

Conclusions:

• Local anesthetic efficacy and duration are influenced by chemical structure and metabolism.
• Understanding these properties is crucial for safe and effective clinical application.
• Further research into optimizing local anesthetic properties and minimizing adverse effects is warranted.