Final answer:
Lidocaine, or lignocaine, is an analgesic that, when combined with adrenaline or epinephrine, can extend the duration of anesthesia in surgical settings. Adrenaline, a hormone produced by the adrenal glands, induces vasoconstriction and is essential for the fight-or-flight response.
Step-by-step explanation:
Lidocaine, also known as lignocaine, is an analgesic that reduces pain without the loss of consciousness. When combined with adrenaline (also known as epinephrine), its effects are enhanced. Adrenaline is a non-steroid catecholamine hormone produced by the medulla of the adrenal glands, and it plays a significant role in the body’s fight-or-flight response. Adding adrenaline to lidocaine preparations serves to extend the duration of anesthesia by causing vasoconstriction at the site of injection, which delays the absorption of lidocaine, allowing it to work longer.
Adrenaline and epinephrine are interchangeable terms, with epinephrine being the preferred nomenclature in the United States, while adrenaline is more commonly used in Great Britain. It is interesting to note that, in the past, 'Adrenalin' was a proprietary drug name in the United States. Epinephrine stimulates the fight-or-flight response, increasing blood glucose and diverting blood to the muscles. It is also a powerful vasoconstrictor. The combination of lidocaine with epinephrine is particularly useful in surgical procedures to both numb the area and to minimize bleeding due to the vasoconstriction caused by adrenaline. It is important to be aware that both epinephrine and norepinephrine can have significant effects on the cardiovascular system.