The best advice I can think of is to ask your doctor who is doing the surgery. You need to be honest with him about what you are doing and why you are doing it. There may be a slight possibility the cleanse will affect your recovery, but this is a rather unique situation and you need professional advice. The only thing I can tell you is that the sleeping pills may make your stomach very upset, and that would be contradictory to the purpose of their use. Please speak to your doctor.