I also would consider some sort of electrolyte/rehydration powder one of those in-between things. Although not a drug, rehydration is one of the most effective things you can do for any number of situations that may afflict someone out on the trail. Even simple things, from a headache due to a bit of dehydration, to a sunburn, to low blood sugar, to a bout of diarrhea, etc. could benefit from effective rehydration (which is not necessarily synonymous with "electrolyte replacement," but few of us truly need that vs needing rehydration)