In 1916, 5, 5'-phenylethylhydantoin was introduced under the trade name “nirvanol” as a hypnotic and sedative. This drug shows certain advantages in comparison with the related disubstituted barbituric acids, but its wider application has been curtailed by its toxic properties manifested by what is commonly referred to as “nirvanol disease.” Several attempts have been made to modify and improve phenylethylhydantoin by replacement of ...
