Effect of ale is ... er ... getting drunk! (7)
I believe the answer is:
Here is my best explanation:
'effect' is the definition.
('effect'->'realize' is in my internal thesaurus and 'ize'->'ise')
'ale is er getting drunk' is the subsidiary indication.
'getting drunk' indicates anagramming the letters.
'aleiser' is an anagram of 'realise'.
'of' is the link.
(Other definitions for realise that I've seen before include "Come to understand - see liar (anag)", "Achieve; turn into cash", "Comprehend and convert into money", "Achieve, make", "Grasp", "Bring to fruition", "See lair (anag)", "Be fully aware of or convert plan into fact", "Ears lie (anag.)" and "Become aware of; fulfil (S, not Z)".)