Hello. Non-medico here; I actually came across this thread from a similar thread in the pre-pharm forum. (Non-pharm too: I'm an Rx delivery driver for a pharmacy.) Still, thought you might enjoy a bit from a 'customer' viewpoint.
See, my wife --- type 2 diabetic, some blood pressure problems --- has been chosen by the Lord to be the football in a game called "Stump The Doctors." If there's an adverse reaction to something, and it's really obscure, well... That's my wife's role in the universe: to suffer that adverse reaction.
Case in point:
Wife was getting violently ill every three weeks, like clockwork: yakking up bile, febrile, muscle weakness. Off to the ER we go. She would be held overnight, tested for this 'n' that, instructed to discontinue all meds for 72 hours, liquids only for same, then soft foods. Come back if there are still problems.
So... She'd come home, follow instructions, and be just fine. Would contact her GP and told to continue with her normal meds regimen. 2½ weeks later, back to the ER.
After about six months of this gig, she happened to draw the same ER doc she'd seen the first time; he remembered her. After looking at her recent history, he instructed the lab to test for everything, no matter how unlikely. By gum, test for prostate cancer: test for everything and anything.
The result: my wife had potassium poisoning. 😕
Buh-hunh? It took some work, but they finally figured it out:
It was her BP medication. A side effect so rare it wasn't even indexed was the cause. Apparently, the BP med prevented her body from correctly processing potassium in her blood stream. The potassium would build and build, until it hit a critical mass and she'd get sick. This reaction would only occur in 1 of 180,000 patients, which meant it never got mentioned in the normal info sent out.
So yeah, that's my wife's role in this existence: Stump The Doctors. It's her role to keep y'all on your toes, even though she really wishes it wasn't. 🙄