I got advice from a pharmacist five years ago, and immediately bought a very small Styrofoam cooler.  The pharmacist pointed out that the "safe" storage range for most prescriptions drugs is room temperature in a regular house, so a small cooler without ice will achieve this for you.  The only exception is if I have left my rig in an airport for a few days in heat, and in that case, I tuck in a couple of very small ice packs and cover the cooler with a couple of towels. 

I refill my prescriptions for 90 days and have a few I take as needed, so they may need to last more than 90 days.  I just wanted to make sure my stuff does not prematurely deteriorate.

  On 8/24/2016 at 4:35 AM, hobopals said:

I'll try to answer and thank everyone for their input in one post. I wasn't trying to refrigerate, just keep medications from extreme heat. I think I've gotten the answer from what everyone pretty much indicated. A cooler will be cooled enough at night to keep the drugs in it to keep extreme heat from being a problem while I'm driving during the day or if I leave the trailer for a day to sight see. I have a good feeling about this advice and will not use an ice pack. As always, everyone's responses are not only right on the money, but much appreciated by this poster. Thank you, all, for responding.

I have a styro cooler in the back of my van and keep it stocked with bottles of water.  if the top is left open at night and closed early in the day the contents stay cool all day.  I would keep a couple of bottles of water with the meds for "thermal mass" to help the load through the day.