What is the purpose of vasoconstrictors in local anaesthetics?

The purpose of vasoconstrictors in local anaesthetics is to narrow the blood vessels, which helps maintain the effectiveness of the anaesthesia for a longer duration. When a vasoconstrictor is added to a local anaesthetic, it reduces blood flow to the area where the anaesthetic is administered. This decreased blood flow minimizes the absorption of the anaesthetic into the bloodstream, thereby prolonging its action at the site and reducing the likelihood of systemic side effects. Additionally, by controlling the spread of the anaesthetic, vasoconstrictors help ensure that it remains localized to the intended area, leading to better pain control during procedures.

The roles of taste enhancement, reduction of anaesthesia time, and impact on nerve transmission are not the intended functions of vasoconstrictors in this context.