My DH uses the FRIO. His pens can be room-temp once he's started them; they only need to be refrigerated before use. Be aware that any "ice pack" you use even for meds will count towards your 3-1-1 allowance unless it is completely frozen solid at the time you go through airport security. Depending on how far you live from the airport that may be possible, but hard to control for the return flight. Liquid or gel packs that have started to thaw may be required to be tossed. I've known people who travel with a bag of frozen peas as the "ice pack" because it remains in a solid state even after thawing. The FRIO helps keep the item(s) at the temp it was when put into the FRIO -- if you take something directly out of the fridge and put it in the FRIO it should stay fridge temp for at least a few hours up to a couple of days. There are various sizes/styles of FRIO -- you can check them out online.
I don't know what med you use but insulin should NEVER be frozen. CMs onboard will NOT take responsibility for a guest's medication. Onboard, the mini refrigerators should be fine for most medications requiring refrigeration; however as with any hotel or mini-fridge, be careful and check the temp regularly and keep items away from the very back where it may freeze.
Another option I've read in suggestions is a travel med cooler, which essentially is a tiny portable fridge. It gets plugged in once you arrive at your stateroom to maintain the temp. It wouldn't help for air travel, though.
Enjoy your cruise!