intrathecal

adjective

in·​tra·​the·​cal ˌin-trə-ˈthē-kəl 

-(ˌ)trä-

: introduced into or occurring in the space under the arachnoid membrane of the brain or spinal cord

intrathecal drugs

intrathecally

ˌin-trə-ˈthē-k(ə-)lē 

-(ˌ)trä-

adverb

Examples of intrathecal in a Sentence

Recent Examples on the Web

Her plan includes five phases: induction (weekly chemotherapy), consolidation (weekly chemotherapy plus spinal taps with intrathecal methotrexate) and a third phase every 10 days, depending on her blood counts. —Jordan Greene, People.com, 2 June 2025

Word History

First Known Use

1887, in the meaning defined above

Medical Definition

intrathecal

adjective

in·​tra·​the·​cal -ˈthē-kəl 

: introduced into or occurring in the space under the arachnoid membrane of the brain or spinal cord

intrathecal chemotherapy and cranial irradiation

—The Journal of the American Medical Association

intrathecally

-kə-lē 

adverb