Horrid pain sir? Take this (7)

I believe the answer is:

aspirin

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'horrid pain sir? take this' is the definition.
The definition suggests a singular noun which matches the answer. I also know that 'pain' relates to this answer.

'horrid pain sir?' is the wordplay.
'horrid' indicates an anagram.
'pain'+'sir'='painsir'
'painsir' anagrammed gives 'ASPIRIN'.

Can you help me to learn more?

(Other definitions for aspirin that I've seen before include "Analgesic over in Paris" , "Pain relief" , "Commonly used pain-killer" , "Anti-inflammatory tablet" , "number" .)

I've seen this clue in The Sun.

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