Colonoscopy prep did not work . drank 64 ounces and took four laxatives . did not use the bathroom once . what should i do ? i need this test done

Glycerin suppository: Buy some glycerin suppositories, use one as directed. That should open the floodgates for all of the things you took from above to empty your colon.

Enema: Try a Fleets Enema (these are sold over-the-counter). You can also take over-the counter magnesium citrate orally or several servings of Miralax (polyethylene glycol) to augment the preparation. Since you already took what should be an adequate amount of preparation orally, I would suggest aproaching the problem from the other end.

Reschedule Colonosco: Without a good bowel preparation, colonoscopy will not give enough information. Speak to the doctor doing the colonoscopy and see if this should be deferred

Call your doctor: Although it's unlikely to drink 64oz of PEG solution and have no bowel movement, I suppose it's possible. First, make sure your doctor is aware of this immediately. Alternative preps are available, such as Osmoprep, a tablet-based prep which is sometimes better tolerated. Good luck.