If you've not upgraded the rooms, that's very easy to do without putting yourself into danger.
If you're not playing on Survival Mode, you can also rush those rooms a few times to get additional stuff. Later on, when you have near-perfect dwellers with lots of hp and an arsenal of good mid-tier weapons and equipment, plus possible some neat pets if you're lucky, they will require a lot fewer stimpaks and no rad aways at all. Instead, just focus on a few, and give them the best equipment that you have. Sending out too many badly equipped and untrained dwellers is just a drain of resources. If you feel you need to upgrade your science lab and your med bay, then that's probably a sign that you're sending out too many low-hp people who chew through too many stimpaks.