I don't know much about Gliclazide, I'm afraid, though I expect someone will be along in a bit, who does.
When you drink alcohol, your liver concentrates on processing alcohol, rather than dumping sugar, which means that your b/s can go down (sorry if I'm mansplaining, by the way
). Given that gliclazide also lowers your b/s, I guess it could produce a Double Whammy effect and lead to a hypo. All I can suggest is that you keep an eye on things and maybe measure your b/s at regular intervals throughout the evening and have something edible to hand, in case you need a boost - but then be careful you don't over do it the other way.
Have you had hypos at all? Presumably if you have, then you'll be familiar with the warning signs and maybe you could get a friend to keep an eye on you as well. I'm T2, and control things by diet and exercise. I don't have hypos but I am told that, if I don't eat properly, I start getting quite stressed; I don't notice it myself but my family do, and order me to eat, so try and recruit an observer to tip you the wink.
Notwithstanding all this, I hope you have a great evening with your friend.
