<unk>  is an orally active, long acting vasodilating drug.<unk>  is metabolized in the liver to the active metabolite SIN-1. SIN-1 is an unstable compound that releases nitric oxide upon decay as the actual vasodilating compound.
Molsidomine
Linsidomine
Tolperisone
Scopolamine 
Rescinnamine
Clofoctol
Glycopyrrolate 
Deanol