If you take insulin or certain medications to control diabetes, however, drinking alcohol can put you at risk for low blood sugar. This is especially true if you drink on a empty stomach or don't have adequate carbohydrates because alcohol reduces your body's ability to mobilize glucose from storage. That depends on the other ingredients in the product. Something can be free of added sugars but still have other ingredients that supply carbohydrate which will ultimately digest and turn to sugar in the blood. Look at the label for the grams of total carbohydrate.
Sugar alcohol is a class of carbohydrates that includes mannitol, xylitol, isomalt and sorbitol.
These carbohydrates tend to impact the blood sugar to a lesser extent than does sugar. However they are still a form of carbohydrate and digestion will still produce some glucose for the blood. Products that contain sugar alcohol often claim they are sugar-free, but that does not mean the same thing as carbohydrate free. To treat low blood sugar you will want to eat a form of carbohydrate that is easily digested and absorbed so that the sugar will enter the bloodstream quickly. Do not use chocolate bars, ice cream or cookies, all of which contain significant amounts of fat, which slows down the digestion of the sugar.