People have taken it with alcohol, Mahakali did the other week with gin, there's an old report of someone downing a glass of scotch with sn in it and he died, and I'm sure I remember another where someone did it after beer.
I think the prinicple is that you don't want too much liquid in your stomach, you want it to get to your intestines as fast as poss, and also alcohol can react with sn and start to convert it into not sn - which means there's less for you to absorb and a chance it wont work.
However, if you search through the forum you'll find the deadly quantity required per kg of body weight, and for most people you only need 4gms to 10gms. The 25gms is to make it as fast and likely to succeed as possible.
So in summary it will probably still work with alcohol, but there's a chance it might not, it would depend on quantity of sn and it's purity, quantity of alcohol and its strength, and whether it made you throw up.
So in other words, I have no idea.