In the specific European country I was born we have two very common barbiturate based tranquilizers that are in use even today and they both contain more than one chemical, some to potentiate and some to discourage abuse. As far as relaxation goes there is a medication that contains 80mg Valerian and 20mg Phenobarbital and many, many people take it for anxiety relief. Another is mostly used for sleep though its not uncommon for people to take the following which contains 4 different substances (amobarbital being just one) while the others I recall to be propranolol 15mg, atropine 0.2mg, ergot 0.30mg and 25mg amobarbital sodium. I've had both and with the amobarb, the atropine seems to overpower anything in doses of anything over 2 pills, (50mg) and maybe a standard beer.
The interesting thing is they still make pure phenobarbital 100mg (instant release) and still widely prescribed! I know a neighbor from back there who is on 2x 100mg phenobarbital for sleep (insomnia). The fucked up thing is that I have yet to find any barbiturates besides the phenobarbital that can be found in their pure form (without any other chemicals in them). Hopefully they haven't come to light (to me) and its a matter of finding out if we have any, though I am a bit sad to say that I would have known by now.