I always carry ibruprofen or naproxen: sometimes in a branded travel-size bottle, sometimes in a smaller unmarked vial, occasionally in the "single-serving" paper packets. Never had a problem with any of them domestically.
Many years ago (pre-9/11™) at a small foreign airport a single pill was taken for "testing" but I was then released. I suspect the 50ish officer mistook light-blue generic naproxen for Viagra. Always wondered how that worked out for him...