I love learning how to do things it just never occurred to me to do before. In this case, it's making my own cough drop. The thing about cough drops is that they are just specially flavored candy. Some may be vaguely medicinal, but there's something to be said for having your favorite herb, spice, or tea inside the lozenge that's soothing your throat. Normal candy making rules apply, so you can follow the normal rules for ingredient substitutions and dealing with changes in the environment (or not) as necessary.