A beer has about 13 grams of carbohydrate and sweet liqueurs have sugar added. If you take insulin or certain medications you may be at risk for low blood sugar if you drink alcohol, especially if you drink on an empty stomach or don't have adequate carbohydrates. 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 a 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.