As I said, I don't think it should be a problem to mention it (though you need to be prepared for the possibility someone may take exception to it). I just wouldn't dwell on it in your shares, and it sounds like you don't intend to.
Some people I know who mention drugs as part of their story preface it with sort of a disclaimer, like so: "This is AA, not another program, so I don't intend to talk in any detail about my drug use, but it is part of my story. When I was drinking, it led me to abuse drugs as well, which was one of the ways alcohol took over my life." And then keep the focus of the share on your recovery from alcoholism.