Likewise, I was never told to avoid taking anything with my levothyroxine besides
food and calcium/multivitamin (basically just not at the same time, but I could still have a multivitamin). I've also never had a problem taking benedryl (besides that it knocks me out) or any other drug with my hypothyroid meds.
If you're on a drug for your hypothyroidism, there is this nifty tool at the top- under drugs, you can find drug interaction.