Gastroscopy and colonoscopy on same day.

My GI here in Tokyo offers a gastroscopy and colonoscopy on the same day, avoiding the day-before prep. During the gastroscopy they inject laxatives directly into the duodenum. When the gastroscopy is finished the patient then waits to have a bowl movement(s) followed by the colonoscopy. The whole thing takes about 2 hours, plus time to shake off any sedation.

I don't know if this is offered in other countries. Has anyone done this? I'm due for both tests.