system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 How do painkillers kill the pain without specifically being linked to a body part?
gpt
Painkillers are a broad term. There are different classifications. 

Steroids can act as painkillers by slowing and reversing inflammation, which reduces pressure in the affected area, and thereby pain. 

NSAIDs work in a different way to do the same thing

Opioids work in the brain by changing the pathways which process the sensation of pain. 

Topical painkillers like novocaine block pain signals in the local nerves from getting to the brain at all.