It depends what type of alcohol - you'll obviously need more insulin for a carb-loaded beer than for a diet coke with vodka, for example. The only extra consideration is in relation to the cautions about alcohol dropping your blood sugar later in the night or the next day. For me, it doesn't seem to do this and if anything it just makes my BS rise in the same way as any other food item with the same amount of carbs would. Unfortunately it's trial and error but, as with all things, probably best to play it safer and have a little less insulin that normal first until you figure out how you respond.