Table 1: Drugs currently available (post-2010) or under clinical trials for PAH.

Drug Name	Type of Drug	Stage	Route of Delivery	Working Mechanism	Work on animal Models
Amlodipine	Calcium Channel Blocker	Currently Available	Oral	CCBs prevent Ca^2+ entry into cells, Ca^2+ will not serve as an intracellular messenger. CCBs will act as a smooth-muscle dilator.	Tested in rats [25].
Epoprostenol	Prostanoid	Currently Available	I.V.	Acts as a selective IP-prostacyclin receptor agonist. This will promote vasodilation and inhibition of vascular smooth muscle cells.	Tested in pigs [6,15].
Treprostinil	Prostanoid	Clinical Trial (phase 3)	I.V. or Inhaled	Acts as a selective IP-prostacyclin receptor agonist. This will promote vasodilation and inhibition of vascular smooth muscle cells.	Tested in male and female rat models [6].
Macitentan	Endothelian Receptor Antagonist	Clinical Trial (phase 2)	Oral	ERAs will either interact with ERA-A or ERB. When the antagonist interacts with either of these receptors, it will either promote vasoconstriction or vasodilation – respectively.	Work in rat models [2,19].
Ambrisentan	Endothelian Receptor Antagonist	Currently Available	Oral	ERAs will either interact with ERA-A or ERB. When the antagonist interacts with either of these receptors, it will either promote vasoconstriction or vasodilation – respectively.	Work in rat models [16].
Riociguat	Phosphodiesterase-5 (PDE5) Inhibitors	Currently Available	Oral	Prevents hydrolysis of cGMP. cGMP prevents vasoconstriction. Nitric oxide is release as a mediator which will promote vasodilation.	Work in rat models [2,16].
Sildenafil	Soluble Guanylyl Cyclase stimulants	Currently Available	Oral	sGC stimulator will promote NO binding on heme group. Allows for cGMP synthesis, which will interact with the Nitric oxide cycle and promote vasodilation.	Work on mouse models [2,7,11].