From what I understand the cayenne is a necessary component to achieve a cleansing state. Recently I read a bit that having the cayenne loose was better since the saliva was activated and the stomach knew what to expect. If the cayenne is encapsulated it gets dropped into the stomach with no advance warning and can cause problems when the capsules melt. Try using a small amount in the lemonade and GRADUALLY working up to a full dose as you get used to it. Also you might try to find a less hot type to begin with. It does get easier.
One thing that cayenne does do it dialate the blood vessels so that stuff moves thru faster. Check out this link: