Lasting side-effects of purple tea (9)

I believe the answer is:

perpetual

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'lasting side' is the definition.
'perpetual' can be an answer for 'lasting' (thesaurus). I am not certain of the 'side' bit.

'effects of purple tea' is the wordplay.
'effects of' is an anagram indicator (I've seen 'effects' mean this).
'purple'+'tea'='purpletea'
'purpletea' anagrammed gives 'PERPETUAL'.

Can you help me to learn more?

(Other definitions for perpetual that I've seen before include "Constant" , "Everlasting" , "Continuing forever or indefinitely" , "Incessant" , "Continuous (motion impossible!)" .)

I've seen this clue in the Sydney Morning Herald.

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