A dizzy spell? I run in for drug (7)

I believe the answer is:

aspirin

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'for drug' is the definition.
(aspirin is a kind of drug)

'a dizzy spell? i run in' is the wordplay.
'a dizzy spell?' becomes 'asp' (I can't justify this - if you can you should believe this answer much more).
'run' becomes 'r' (cricket abbreviation).
'asp'+'i'+'r'+'in'='ASPIRIN'

Can you help me to learn more?

(Other definitions for aspirin that I've seen before include "Synthetic analgesic" , "Headache killer?" , "Analgesic over in Paris" , "answer to pain?" , "Anti-inflammatory drug" .)

I've seen this clue in The Independent.

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