Just wanted to warn others about the dangers of taking Fleets Phospho-soda for a colonoscopy prep if you are also taking an ACE inhibitor (e.g., lisinopril). Eighteen months ago, I went in for a routine colonoscopy. My annual exam one month prior showed that my kidneys were fine. HOWEVER, the GI doc gave me Fleeets Phospho-soda as a prep, despite the fact that I told her that I was taking lisinopril for mild hypertension. What I did not know at the time is that there is an FDA warning and a "Dear Doctor" letter sent to physicians warning them that, in rare cases, the combination of Fleets and ACE inhibitors leads to acute kidney failure. Within 48 hours of the procedure I did, in fact, develop acute kidney failure which resulted in my spending 11 days in the hospital, and am left with late stage 3 chronic kidney disease. This means that I have to be on the renal diet for life (it's VERY restrictive and difficult), get injections of a synthetic hormone called Aranesp because my kidneys don't make the hormone that is necessary for the manufacuture of red blood cells, get IV infusions for iron deficiency, and battle edema, bruising, and fatigue. The kidney disease also increases my risk of cardiac disease and death. Despite all the data, many GI docs refuse to change their practice, because "the risk is so rare." That's true, but I am Exhibit A that it DOES happen. The thing is, it is very easy to avoid this event: either go off your hypertension medication for a few days before the procedure, or, if your pressure is too extreme to go off your meds for a few days, take an alternative prep (e.g., Go-lytely).