I tried to find an answer online, but found quite a few different claims. One site said this: "Although the plasma half life of spironolactone itself is short (1.3 hours) the half lives of the active metabolites are longer (ranging from 2.8 to 11.2 hours). Elimination of metabolites occurs primarily in the urine and secondarily through biliary excretion in the faeces.

If you need more info, just search for Spironolactone "half life" to see how long it will take for your body to excrete the drug (or ask your pharmacist). This might also be dose dependent. If you find out anything, please post for the rest of us :) Thanks!