system
Given the following post, respond as if you're commenting on Reddit:
human
Why do a lot of numbing chemicals/medicines end in the word “Caine”?

Examples: lidocaine, novocaine, benzocaine, tetracaine ect.
gpt
The 'caine' part is from cocaine.  


Etymonline:  


novocain (n.)
  
also novocaine, 1905, originally a trademark name for procaine (by Lucius & Brüning, Hoechst am Main, Germany), from combining form of Latin novus "new" (see new) + -caine, abstracted from cocaine. As a local anaesthetic, it began as a substitute for cocaine.