5 ml of Benadryl 1 hour before bed might knock you out?
Edit: My comment was not all that well thought out. I just recently observed my kid sleep instantly once the cough medicine kicked in. As others have pointed out, don't use it consistently, could cause dementia and is super dangerous in high doses.
Yeah this is really scary, but people get desperate when they can't sleep properly for weeks, and it's like $200 just to set foot inside the clinic to get some actual help