Here's the first patient of my career whose case was interesting enough to write about.
I worked with a lady who had been admitted from the Emergency Department with severe abdominal pain. This raised red flags because the patient had a certain ongoing condition, and the pain could have indicated serious complications. She was quickly admitted to the hospital, and by the time I met her, the team was already ruling out those complications.
Less happily, they also ruled out everything else. Nobody could find anything wrong with her. There was nothing apparent to physical examination, blood tests, lab tests, ultrasound, or any of several fancy scans. She didn't have appendicitis, colitis, peritonitis, diverticulitis, gall stones, kidney stones, bladder stones, ovarian torsion, ectopic pregnancy, or even constipation. Only pain, and lots of it.
She didn't appear to be a drug seeker. She did not have any of the common signs of that, like requesting a specific drug, or claiming an allergy to the boring low-end stuff. All the docs and nurses who encountered her were pretty sure she was authentically hurting. Even the hospital's pain management specialist came to assess her, and stated his belief that she was suffering real pain. They just couldn't find out what was causing it.
The patient expressed grateful relief after oral non-narcotic medication, but the effect did not last long enough. Her pain kept returning sooner than she could safely be given the next dose. So to check how the pain responded to something else, the physician ordered a different medication, this one by IV.
Now be aware that before giving any drug by IV push, the nurse must first check that the IV catheter is still patent and correctly placed. This is done by injecting a few milliliters of sterile saline into the IV port.
The patient wasn't watching closely and didn't realize we were going to inject saline before the drug. As soon as she felt the first cold liquid go up her arm, she instantly stopped moaning and holding her belly. She said, "Oh, that's so much better." Her racing pulse slowed and her blood pressure came down a bit. And she shortly rolled over and fell asleep.
I'll say that again: she felt better and was able to sleep after just 2 ml of salt water. Placebo effect FTW.
Here's where the ethical issue shows up.
How about we hold the drugs, stick with the saline, and let her think she's getting a narcotic? All drugs have side effects. A small saline injection is a whole lot safer, no one's allergic to it, and as a special bonus it costs less. Since it works for this patient, there's no reason to use anything else... right?
It turns out that, according to US medical ethics as I've been taught them, there is one right answer. It's one of those questions with no big gray area, rather a clear solution and a simple rationale.
I'll post the answer in the comments in case you want to think about it first.