<unk>  (Presidon, Persedon) is a psychoactive drug invented in 1949.
An improved method of manufacture was patented by Roche in 1959. It was used as a hypnotic or sedative and presumed to be less toxic than barbiturates. Today, this substance is no longer used. Agranulocytosis was sometimes reported as adverse effect.
Pyrithyldione
Bithionol
Prenalterol
Ethynodiol diacetate
Bumadizone
Pyritinol
Ammonium hexachloroplatinate
Bicisate dihydrochloride