You never know what will bite you. I started a mild blood pressure drug over a year ago (for a kidney issue, not blood pressure) & sweated dealing with that. It was no problem.
I was also started on about 50% of the normal dose for my weight of Synthroid, used for hypothyroidism. Never gave that any thought. Guess what: Instant Disqualifier; must be referred, and cannot be issued by the doc on the spot. Fortunately I paid an unofficial visit to the AME prior to the actual exam, & we were able to get it set up so that he could make a call to the regional office & get verbal approval.
I got my medical, but was told to expect a letter of 'denial/but we'll let you fly anyway' sometime in the next month or two.
It's truly bizarre (according to real, actual doctors) what the FAA considers disqualifying.