Last year, on my first cruise, I took the "LESS DROWSY" Dramamine. Of course I didn't take it soon enough and got really ill with the 14' seas we had the first couple of days. It finally kicked in after an unpleasant episode with one of those little white barf bags and a 6 hour nap. From then on, it was like walking on sunshine! I did notice that if I let myself nap, it would be a deep sleep for several hours but while I was up and moving around, I didn't notice they made me sleepy.
I did the patch on my Key West vacation (fishing charters) and do not recall getting sleepy. I'll take the patch with me on my upcoming Oct. cruise. On the RCI Raphsody, they would give you seasickness pills at the purser's desk. Do they do that on Carnival?