I was on a very mild antispasmodic for stomach irritation back in 2005 that my AME didn't even recognize as a problem. Feds yanked my medical certificate. Went off the meds and did the dance of sending the FAA paperwork and all of that. They wanted me off it six months with a follow-up from my physician showing I was fine without it. So all told, that was a 7-8 month ordeal. Granted, that was many years ago and I'm sure the FAA has improved since then. Not really, that was a joke.
This is why I fly BasicMed today. I don't even want to bother with the Fed.