Agreed jackieofalltrades, I also do that with shoes.
For those that need to carry, say, 48 hrs of meds. Perhaps a kids size backpack? That could sit at your feet under the seat in front. For emergency evac, you could sling it over one shoulder but it would not be big enough to block other people, or to bash them?
Further, make sure that you have duplicate documentation for all your meds in that mini rucksack. I take important travel documents as paper and scanned as PDF on a USB memory stick so that I can print off copies from any computer. I may have also uploaded those files to a password 'box' online. This includes details of my travel insurance and numbers I have to ring if things have gone really bad. If your meds are time critical, consider wearing a medic-alert braclet - even if only when flying.
Including a scan of your prescriptions and a covering letter from your doctor would be easy. If things went bad rescuers would find the copies of your meds in the mini bag (with your name on the outside) and that would also state the regimen. This would speed their being able to identify your condition and provide remedy.