Which statement about intrathecal clonidine as a spinal analgesic is true?

Which statement about intrathecal clonidine as a spinal analgesic is true?

• A. It is not analgesic when used intrathecally
• B. It provides analgesia when used intrathecally
• C. It has no analgesic effect
• D. It only provides sedation

Answer: (B)

Intrathecal clonidine provides analgesia by acting on spinal alpha-2 receptors in the dorsal horn, where it dampens nociceptive transmission. It reduces release of excitatory neurotransmitters such as substance P and glutamate, leads to hyperpolarization of pain-transmission neurons, and often enhances or prolongs the effect of local anesthetics when used together. While it can cause sedative and hemodynamic effects, its proven action intrathecally includes analgesia, not just sedation. So the true statement is that it provides analgesia when used intrathecally.

Intrathecal clonidine provides analgesia by acting on spinal alpha-2 receptors in the dorsal horn, where it dampens nociceptive transmission. It reduces release of excitatory neurotransmitters such as substance P and glutamate, leads to hyperpolarization of pain-transmission neurons, and often enhances or prolongs the effect of local anesthetics when used together. While it can cause sedative and hemodynamic effects, its proven action intrathecally includes analgesia, not just sedation. So the true statement is that it provides analgesia when used intrathecally.