Talk to a doctor! Androcur and Spiro are completely different beasts, with Androcur specifically being an anti-androgen and Spiro being a diuretic that also happens to have great anti-androgen affects. While both are usually tolerated OK, only a doctor can determine if making the switch would be dangerous or not.
Just a question: What slow effect did you experience with Spiro? Sure, it may take a week or two for your body levels of spiro to get up to an active level, but I don't know of spiro being specifically slower as an anti-androgen in any real meaningful way (i might be wrong. anyone else have opinions?)