Our doctor prescribes Suprep but also uses Miralax in Gatorade as an alternative choice. 64 oz. total of Gatorade that you drink twice at 32 oz. each time (4 8oz. glasses, 10 or 15 minutes apart), along with the clear liquid diet starting the day before. In addition to the Miralax, instructions include using 2 Ducolax stool softeners before bed on each of the two nights before the test. (
The Gatorade cannot be red or purple or orange.)
I tend to "study" for the test by cutting back on what I eat for a couple of days ahead.
For my last one, I opted for the Miralax instead of the Suprep (aka
ColonBlast 
) I think it was a lot easier than the Suprep I used 5 years before. The Miralax route worked fine.
Re. Suprep though, which I guess has to be mixed with water -- the doctor sends a packet of instructions that includes a list of things that might help if using Suprep. Here is what it says:
Things that can help. . .
-- Always chill the bottle and use a straw.
-- Cutting a lemon or lime wedge to bite into a little between sips.
-- Having a yellow or green popsicle, Italian ice, Slurpee, or Jell-O and taking a bite after each sip.
NO red or purple or orange.
--Drinking a
clear liquid after each sip. The liquid includes apple juice, Gatorade, bouillon -- must be a doctor approved choice and again,
No red or purple or orange.
-- Suck on a hard candy.
NO red, purple or orange, something like a Jolly Rancher, it says. (I am not clear on this one because I tend to go "crunch" on hard candy. I don't like hard candy anyway. How will I ever be able to fulfill my role as an old lady in the theater seat behind you annoyingly unwrapping hard candy.
)
The last thing on the list says. . .
. . .If nausea exists from the Suprep, lie on your left side and take a break. Slow down. The prep does not have to finished in 2 sips.
Warning: I am not a doctor. This information is from the gastro we have been going to for colonoscopies for years. Please check everything with your own doctor.
And best of luck.
Boomer