Dextrose is a simple sugar and is recommended for treating hypos whereas glucose is a complex carbohydrate and to be avoided unless there is nothing else.
According to my failing memory there are two optical isomers (that is, same atoms in the molecule with a different arrangement of bonds). That is, they twist polarised light in different ways.
Dextrose which twists light to the right.
Levulose which twists light to the left.
However the Internet, as usual, doesn't seem to be sure.
As far as I can tell at the moment:
Dextrose=Glucose
Levulose=Fructose
Both are monsaccharides which can combine to form the disaccharide sucrose.
However I am happy to be corrected.
Interesting that optical isomerism can affect the way that monosaccharides are processed by the body.