Final answer:
Clonidine, when used with local anesthetics for peripheral nerve blocks, inhibits C-fibres and A delta fibers, which enhances pain blockade.
Step-by-step explanation:
The question pertains to the effect of Clonidine when used in conjunction with local anesthetics in peripheral nerve blocks. Clonidine is known for its sympatholytic properties and is used to treat conditions such as hypertension, anxiety, pain, and attention deficit hyperactivity disorder. When added to local anesthetics, Clonidine can enhance analgesia. Specifically, the correct answer to the question '16A-115 Clonidine in peripheral nerve block' is 'A. Inhibits C-fibres and A delta.' This is because Clonidine aids in blocking pain transmission by inhibiting these pain fibers, thereby enhancing the analgesic effect of the nerve block without causing a loss of consciousness or significant sedation.