Question 49

The route by which a drug is introduced into the subarachnoid space surrounding the brain and the spinal cord is intrathecal.

Intrathecal administration involves delivering medication directly into the subarachnoid space, allowing for rapid effects on the central nervous system.

A) intraperitoneal

Intraperitoneal administration refers to delivering substances into the peritoneal cavity, which is not relevant to the subarachnoid space. This method is typically used for certain types of chemotherapy or for administering insulin in some animal studies, making it incorrect for this context.

B) intravenous

Intravenous administration involves injecting substances directly into the bloodstream. While it can quickly distribute drugs throughout the body, it does not target the subarachnoid space specifically, thus making it an unsuitable choice for the question.

C) intrathecal

Intrathecal administration is the correct method for introducing a drug into the subarachnoid space. This route is specifically designed to bypass the blood-brain barrier and provide direct access to the cerebrospinal fluid, making it ideal for certain medications used in the treatment of neurological conditions.

D) intratracheal

Intratracheal administration involves delivering substances directly into the trachea, which is used primarily for respiratory treatments. This method does not relate to the subarachnoid space and is therefore incorrect in the context of the question.

Conclusion

Intrathecal administration is the only option that accurately describes the method of drug delivery into the subarachnoid space, allowing for targeted effects on the central nervous system. All other options focus on different anatomical sites or methods of administration that do not achieve the specific goal of accessing the cerebrospinal fluid directly.