I used soma, Percocet and a fentanyl patch for lower back pain for about 8 to 10 years. About a year and a half ago my Dr. stopped prescribing soma and replaced it with parafon forte. Last July I had to have emergency surgery for a peptic ulcer. The surgeon that did the operation said the fentanyl patch probably masked the pain. He also said that in another 4 or 5 hours I probably would have died. I had no stomach pain up until that day. Could these drugs being used for that long have caused my ulcer?