Metformin is the drug with the lowest risk of hypoglycemia. It reduces glucose output from the liver and improves glucose uptake in the periphery. If you are reducing carbs while taking metformin your chances of having a problem of hypos is not great. Most people, however, should be able to get off their metformin or significantly reduce it. The other drugs that stimulate insulin production, however, will get you into trouble if you continue to take them in their usual dosages when you start a low-carb diet. Same for insulin. Of course, type 1 diabetics will always need some insulin and severe type 2's may need to continue taking some insulin or meds as well. For most people (type 2), however, getting completely off meds and insulin should be the goal of carbohydrate restriction.
An Atkins induction level of carb restriction is not hard to do. I have been doing it for almost nine years now and would not consider any other way of eating.