Pharmacology Histamine, 5-HT and PGs 53eeb74f prostacyclin agonist which is usually given oral. A Teleprost B Iloprost C Riociguat D Selexipag High-Yield Explanation * Selexipag is the only PGI2 drug which can be given oral route * Prostacyclin analogue like iloprost, treprostinil can be given i/v or s.c or inhaltional route.