i know phenergan knocks me out for days, i take it when i get stung by a bee, and not only do i sleep for a day, i have a couple of days where i feel like im stoned afterwards.
other anit histermines ive had havent been as bad as the phenergan sleep wise....but then again i do only take it when i get stung, so those side effects might be the actual bee sting rathr than the drug *shrugs*