<unk>  (Optimine) is a first-generation antihistamine and anticholinergic that was launched Schering-Plough in 1973.
It was patented in 1967.
It is a predecessor to loratidine, albeit lacking the chlorine atom. Also, it is N-methyl instead of carboethoxyamido.
Azatadine
Loratadine
Tromantadine
Visnadine
Desloratadine
Rimantadine
Alcaftadine
Rupatadine