There is a very common misconception on the Right that the Founders were libertarian. This is because they set up a FEDERAL government with limited powers.
However, the Constitution put very few restrictions on the powers of each state over its citizens. In fact, many pre-Civil War states had laws that we would today consider unconstitutional, including egregious violations of the Bill of Rights (which did not originally apply to the states).
The Founders would in all likelihood have been fully in favor of banning "drugs." They just would have insisted it be left up to each state.