By RAW you can also create Antitoxin. It is suggested you could also create "remedies" with it. Which probably means some kind of antacid, aspirin, or cough syrup, and giving bonuses for using them. Which implies it's some kind of doctor's bag for long term sickness/disease care, while the healers kit is some kind of first response bag for dealing with trauma.
As a houserule: Just fold the healer, herbalist, and poisoner's kits into a "doctor's kit." If you want even more oomph, add in the alchemist supplies.