The prep procedure varies but for a colonoscopy, the prep may be either Golytely, which uses enema as a back up if oral prep does not complete the cleansing. Phosphosoda preps generally include an enema or suppository as part of the prep.
A high colonic can be very effective for cleansing, but will not replace a medicated enema or suppository. Your Physician may agree to plan your test preperation to utilize the Colonic in place of the enema. Include this request among your list of questions you plan to ask at your pre-test appointment, or make the request to his Nurse or assistant (if the test is scheduled without further consultation).
Don't be concerned that your request is "unusual", it is actually a very reasonable request.
I wish my answer was more comforting, but the procedure will require an oral prep (which is medicated), and sedation during the procedure. The most reassuring fact I can offer is that this is a medically necessary and worthwhile test, considering your family history.
For a detailed description of the test procedure go to:
http://health.enotes.com/surgery-encyclopedia/colonoscopy
I hope this answer has been informative if not entirely comforting. Please let me know if I can offer further assistance. Good luck to you.
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