Dave,
Before you run off and get too much medical supplies, for what purpose will your FA kit will serve? Is it for your hiking/backpacking needs, you and the family, etc. I'd suggest if you haven't already done so, get at least a Wilderness First Aid (WFA) or even a Wilderness First Responder (WFR) (depending on the need) certification. WFA is about 18-24 hours and WFR is about 80 hours of training. Well worth it if you're outdoors a fair amount of time.
There are several organizations (even some community colleges) that you can get your cert from, here are a few:
National Outdoor Leadership School (NOLS) Wilderness Medical Associates Stonehearth Open Learning Opportunities (SOLO) Hello All,
What do most people do for medical supplies? We have a first aid kit, but maybe we should have some other items on hand.
Dave