Promethazine/Phenergan (active name/brand) (this stuff, antihistamine, works well, especially if you're combining with an opiate as it will relieve histamine release and thus itching. It is also a sedating drug, 2x 25mg is good for antihistamine purposes (I find)
Codeine - Got a tolerance? Work out a dose, start at 60mg and go from there. Look up Cold Water Extraction if you are going this route, paracetemol/ibuprofen in your system in large amounts is not good and can be fatal moreso in the case of paracetamol overdose.
Not OTC:
Melatonin (actually illegal I hear, although it fucking shouldn't be)
Benzos (obvious, go get a short term script for temazepam if your doctor can script one for ya)
Clonidine (branded catapres) (BP Med/ADHD Med/Sleep Med, It's an Alpha blocker) (100ug puts me straight to sleep if I'm wanting to go to bed, usually I take in combination with promethazine, and usually only on a meth binge as that's why i kept it around -- being an alpha blocker, but alas I have no more!)
As posted above, melatonin is what your body produces at night, as far as i am aware, it regulates the body clock/sleep cycle.... (I'm sure someone will chime in and correct me If I'm wrong here...)
Oh, and I'm only suggesting the above meds for harm reduction purposes, as I have found them to be fairly safe when taken for the purpose of sleep and not RECREATIONAL USE which I would never encourage!

- I'd rather see you take something with my post in mind, instead of overdosing on some hardcore opiates or the like... be safe
