Necessary to take antibiotics before colonscopy if had a hip replacement?

No: There is no indication for using antibiotics before colonoscopy.

Yes: The american academy of orthopaedic surgeons recommends the use of antibiotics before a colonoscopy. "in order to prevent bacteremia, an appropriate dose of a prophylactic antibiotic should be given prior to the procedure so that an effective tissue concentration is present at the time of instrumentation..." http://www.Jasonlowrymd.Com/antibiotics-after-your-joint-replacement-a-must-read.Html.