In regards to a CPAP machine: I put an extension cord in my CPAP carrying bag, and have each item in plastic bags, except for the machine itself. The TSA agents always check out my CPAP. I leave the carrying case open when I set it on the conveyor. The airlines will allow you to carry your CPAP on the aircraft without counting it as a carry-on item. The cruise ships never questioned me on the CPAP.
My wife has a lot of medication that she takes in the morning and evening. I put all her meds in a weekly plastic pill box, plus she takes some extra pain medicine in case she get a migraine headache—those are in the prescription bottle. We have never been questioned about the pills. However, she does have a list of all the pills with the RX numbers in her purse just in case. She carry's her pills in her purse because she would be in a world of trouble if her luggage ever got lost and her meds inside. I hope this makes you a little more comfortable. The TSA agents are VERY STRICT when it comes to liquid.